name: blast phase chronic myelogenous leukemia, BCR-ABL1 positive

description: An advanced phase of chronic myelogenous leukemia. It is characterized by: 1. the presence of blasts in the peripheral blood or bone marrow that are at least 20% of the peripheral blood white cells or of the nucleated cells in the bone marrow respectively, or 2. an extramedullary proliferation of blasts, and/or 3. when there are large aggregates and clusters of blasts in the bone marrow biopsy specimen (adapted from WHO, 2001).


name: breast carcinoma by gene expression profile

category: biolink:Disease biolink:DiseaseOrPhenotypicFeature biolink:BiologicalEntity biolink:ThingWithTaxon biolink:NamedThing

description: A header term that includes the following breast carcinoma subtypes determined by gene expression profiling: luminal A breast carcinoma, luminal B breast carcinoma, HER2 positive breast carcinoma, basal-like breast carcinoma, triple-negative breast carcinoma, and normal breast-like subtype of breast carcinoma.


breast diffuse large B-cell lymphoma

description: A diffuse large B-cell lymphoma that arises from the breast. It is the most common type of primary breast lymphoma.


breast fibrosis

description: Breast fibrocystic change characterized by the prominence of fibrotic changes in the parenchyma.


name: breast mucosa-associated lymphoid tissue lymphoma

description: An extranodal marginal zone B-cell lymphoma of mucosa associated lymphoid tissue that arises from the breast as a primary tumor.


C-cell hyperplasia

description: Neoplastic or reactive proliferation of the C-cells in the thyroid gland. The neoplastic C-cell hyperplasia is associated with familial medullary thyroid gland carcinoma and multiple endocrine neoplasia type II and IIB. Morphologically, it is characterized by the presence of clusters of intrafollicular C-cells with atypical cytologic features. The reactive C-cell hyperplasia is also known as physiological or secondary C-cell hyperplasia and it is associated with conditions that cause hypercalcemia (e.g., hyperparathyroidism).


calcifying fibrous tumor

description: A benign well-circumscribed paucicellular lesion arising from the soft tissues. It is characterized by the presence of fibroblasts, lymphoplasmacytic infiltrates, collagenous stroma formation, psammoma bodies, and dystrophic calcifications.


name: calcifying nested epithelial stromal tumor of the liver

description: A rare malignant tumor that arises from the liver and occurs in children. It is characterized by the presence of nested epithelioid and spindle cells. Desmoplasia, calcifications, and bone formation may also be present.


cardiac rhabdomyoma

description: A well circumscribed benign tumor arising from cardiac muscle. It usually affects children and may be present in the fetus. Depending on tumor location and size, cardiac, respiratory, and hemodynamic parameters may be affected. There is an association between cardiac rhabdomyoma and tuberous sclerosis.


cecum neuroendocrine tumor G1

description: A well differentiated, low grade neuroendocrine tumor (carcinoid tumor) that arises from the cecum. The mitotic count is less than 2 per 10 HPF and/or the Ki67 index is equal to or less than 2 percent.


name: central nervous system anaplastic large cell lymphoma

description: An anaplastic large cell lymphoma that affects the brain, meninges, or spinal cord.


central nervous system neoplasm

description: A benign or malignant, primary or metastatic neoplasm that affects the brain, meninges, or spinal cord. Representative examples of primary neoplasms include astrocytoma, oligodendroglioma, ependymoma, and meningioma. Representative examples of metastatic neoplasms include carcinoma and leukemia.


cerebellar liponeurocytoma

description: A rare, WHO grade II cerebellar neoplasm which shows consistent neuronal, variable astrocytic and focal lipomatous differentiation. It occurs in adults, has a low proliferative potential and usually has a favorable prognosis. (Adapted from WHO)


cervical adenoid basal carcinoma

description: A rare low grade carcinoma that arises from the cervix. It is characterized by the presence of nests of basaloid cells with focal glandular formations.


cervical adenoid cystic carcinoma

description: A rare carcinoma that arises from the cervix. It is characterized by the presence of cystic spaces surrounded by palisaded epithelial cells. The cystic spaces contain eosinophilic hyaline material or mucin. Nuclear pleomorphism, necrotic changes, and a high mitotic rate are also present.


cervical adenosquamous carcinoma

description: An uncommon carcinoma arising from the cervix. It is composed of malignant glandular epithelial cells and malignant squamous epithelial cells.


cervical clear cell adenocarcinoma

description: A rare morphologic variant of cervical adenocarcinoma composed of clear and hobnail cells. It is associated with in utero exposure to diethylstilbestrol (DES).


name: cervical intraepithelial neoplasia grade 2/3

description: A neoplastic process in the cervix characterized by morphologic features of both moderate and severe intraepithelial neoplasia.


name: cervical large cell neuroendocrine carcinoma

description: A rare, aggressive neuroendocrine carcinoma that arises from the cervix and is characterized by the presence of malignant cells with abundant cytoplasm, large nuclei, and prominent nucleoli.


cervical metaplasia

description: Metaplastic changes in the cervical glandular or squamous epithelium.


name: cervical mucinous adenocarcinoma, minimal deviation variant

description: A rare, extremely well differentiated cervical mucinous adenocarcinoma in which most of the neoplastic glands cannot be distinguished from the normal endocervical glands.


cervical villoglandular adenocarcinoma

description: A cervical adenocarcinoma characterized by the presence of a prominent villoglandular pattern.


cervical small cell carcinoma

description: A small cell carcinoma arising from the cervix.


cervical squamous cell carcinoma

description: A squamous cell carcinoma arising from the cervical epithelium. It usually evolves from a precancerous cervical lesion. Increased numbers of sexual partners and human papillomavirus (HPV) infection are risk factors for cervical squamous cell carcinoma. The following histologic patterns have been described: conventional squamous cell carcinoma, papillary squamous cell carcinoma, transitional cell carcinoma, lymphoepithelioma-like carcinoma, verrucous carcinoma, condylomatous carcinoma and spindle cell carcinoma. Survival is most closely related to the stage of disease at the time of diagnosis.


cervical Wilms tumor

description: An embryonal neoplasm arising from the cervix with morphologic features resembling Wilms tumor of the kidney.


chondroid chordoma

description: A slow-growing malignant bone tumor arising from the remnants of the notochord and occurring in the base of the skull. The tumor is characterized by a lobulated growth pattern, myxoid stroma formation, and the presence of physaliphorous cells and cartilage.


chondroid hamartoma

description: A hamartoma that is characterized by the presence of chondroid elements.


clear cell papillary cystadenoma

description: A benign cystic glandular epithelial neoplasm characterized by the presence of neoplastic clear or hobnail cells which form papillary structures. There is no evidence of stromal invasion.


colon Burkitt lymphoma

description: A rare Burkitt lymphoma that arises from the colon.


colon dysplasia

description: A morphologic finding indicating the presence of dysplastic glandular epithelial cells in the colonic mucosa. There is no evidence of invasion.


colon inflammatory polyp

description: A non-neoplastic polypoid lesion in the colon. It may arise in a background of inflammatory bowel disease or colitis. It is characterized by the presence of a distorted epithelium, inflammation, and fibrosis.


colon juvenile polyp

description: A non-neoplastic hamartomatous polyp that arises from the colon. It is characterized by the presence of tortuous and cystically dilated glands, edematous changes, and inflammation.


name: colon mucosa-associated lymphoid tissue lymphoma

description: An extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue that arises from the colon.


colon neuroendocrine tumor G1

description: A well differentiated, low grade neuroendocrine tumor (carcinoid tumor) that arises from the colon. The mitotic count is less than 2 per 10 HPF and/or the Ki67 index is equal to or less than 2 percent.


colon sessile serrated adenoma/polyp

description: A polyp that arises from the colon. It is characterized by the presence of serrated glands and the absence of generalized dysplasia. Some authors have suggested that it is a precursor lesion for some colonic adenocarcinomas with microsatellite instability.


colorectal adenosquamous carcinoma

description: An unusual colorectal carcinoma characterized by the presence of glandular and squamous carcinomatous components. The two carcinomatous components may be admixed within the tumor, or the two may appear separately in different areas.


name: colorectal diffuse large B-cell lymphoma

description: A diffuse large B-cell lymphoma that arises from the colon or rectum.


name: colorectal gastrointestinal stromal tumor

description: A gastrointestinal stromal tumor that arises from the colon or rectum. The majority of cases have spindle cell morphology. Gastrointestinal stromal tumors of the colon are usually advanced upon detection and tend to have a poor prognosis; gastrointestinal stromal tumors of the rectum usually have an aggressive clinical course.


colorectal hamartoma

description: A non-neoplastic, hamartomatous polyp that arises from the colon and rectum. This group includes the juvenile polyp, Peutz-Jeghers polyp, and Cowden-associated polyp.


colorectal juvenile polyp

description: A non-neoplastic hamartomatous polyp that arises from the colon and rectum. It is characterized by the presence of tortuous and cystically dilated glands, edematous changes, and inflammation.


colorectal neuroendocrine tumor G1

description: A well differentiated, low grade neuroendocrine tumor (carcinoid tumor) that arises from the colon or rectum. The mitotic count is less than 2 per 10 HPF and/or the Ki67 index is equal to or less than 2 percent.


colorectal serrated adenocarcinoma

description: A rare, invasive colorectal adenocarcinoma characterized by the presence of a malignant infiltrate with serrated glandular architecture.


name: colorectal sessile serrated adenoma/polyp

description: A polyp that arises from the colon or rectum. It is characterized by the presence of serrated glands and the absence of generalized dysplasia. Some authors have suggested that it is a precursor lesion for some colorectal adenocarcinomas with microsatellite instability.


colorectal squamous cell carcinoma

description: A very rare colorectal carcinoma characterized by the presence of a malignant squamous cell infiltrate.


columnar cell hyperplasia of the breast

description: A columnar cell lesion characterized by the presence of enlarged terminal ductal lobular units with dilated acini. The acini are lined by more than two layers of columnar epithelial cells. Prominent apical cytoplasmic snouts are present. Secretions are often present in the lumina of the dilated acini.


combined lung carcinoma

description: A lung carcinoma characterized by the presence of large or small neuroendocrine carcinoma cells in combination with malignant glandular or squamous epithelial cells.


complex endometrial hyperplasia

description: A hyperplasia characterized by excessive proliferation of endometrial cells, resulting in the formation of complex epithelial structures. Epithelial atypia may be present or absent.


conjunctival disorder

description: Any disorder of the conjunctiva.


conjunctival nevus

description: A benign melanocytic neoplasm that arises from the conjunctiva.


conjunctival squamous cell carcinoma

description: A low-grade squamous cell carcinoma that arises from the conjunctiva. It is the most common primary malignant tumor that arises from the conjunctiva. It usually affects older white males. Excessive exposure to sunlight is a risk factor. Patients may present with a mass, red eye, or pain.


name: cortisol-producing adrenal cortex adenoma

description: An adenoma of the adrenal cortex that produces cortisol. It may be associated with Cushing syndrome. Clinical presentation includes weight gain, round face, easy bruising, muscle weakness, emotional changes, hirsutism, and hypertension.


cribriform carcinoma

description: A carcinoma characterized by the presence of a cribriform architectural pattern. Representative examples include the intraductal cribriform breast carcinoma and invasive cribriform breast carcinoma.


dedifferentiated solitary fibrous tumor

description: A solitary fibrous tumor characterized by the presence of areas of abrupt transition to high grade sarcoma.


desmoplastic ameloblastoma

description: An ameloblastoma with prominent desmoplastic stroma that causes compression of the neoplastic epithelial islands.


digestive system adenoma

description: A sporadic or less frequently familial neoplasm, arising from the glandular epithelium of the stomach, small intestine, biliary tract, colon, and rectum. It is a polypoid or flat circumscribed lesion. Morphologically, it is characterized by a proliferation of neoplastic glandular cells and it is associated with dysplasia. According to the growth pattern, it may be classified as tubular, villous, or tubulovillous. The dysplasia is classified as mild, moderate, or severe. The frequency of malignant transformation depends on the size of the lesion and the degree of dysplasia. Larger adenomas with severe dysplastic changes (sometimes called carcinoma in situ) carry a higher risk of progressing to invasive adenocarcinoma. Gastrointestinal adenomas may present as solitary or multifocal lesions. Familial adenomas tend to be multifocal and carry a higher risk of malignant transformation.


digestive system carcinoma

description: A malignant neoplasm that arises from the epithelium of any part of the digestive system. Representative examples include colorectal carcinoma, esophageal carcinoma, and pancreatic carcinoma.


name: digestive system mixed adenoneuroendocrine carcinoma

description: A carcinoma that arises from the digestive system and is characterized by the presence of a malignant glandular epithelial component and a malignant neuroendocrine component. At least 30% of either component should be present for the diagnosis to be made.


disseminated peritoneal leiomyomatosis

description: A rare, benign process that affects the peritoneal cavity and is characterized by the formation of multiple small nodules that are composed of well differentiated smooth muscle. It usually affects adults in their late reproductive years. Most patients are asymptomatic. The tumor nodules may regress spontaneously.


name: ductal breast carcinoma in situ and lobular carcinoma in situ

description: The co-existence of ductal and lobular carcinoma in situ in the breast, without evidence of stromal invasion.


duodenal adenocarcinoma

description: A carcinoma that arises from glandular epithelial cells of the duodenum.


duodenal villous adenoma

description: A neoplasm that arises from the glandular epithelium of the duodenum. It is characterized by a villous architectural pattern. The neoplastic glandular cells have dysplastic features.


name: EBV-positive T-cell lymphoproliferative disorder of childhood

description: An Epstein-Barr virus-associated mature T-cell lymphoproliferative group of disorders affecting children. It occurs with increased frequency in Asians and Native Americans. It includes the systemic EBV-positive T-cell lymphoma of childhood and the hydroa vacciniforme-like lymphoma.


eccrine porocarcinoma

description: A carcinoma with eccrine differentiation arising from the sweat glands. It may arise de novo or as a malignant transformation of a pre-existing poroma. It usually grows in the legs, buttocks, feet, and trunk and usually presents as an ulcerative plaque. It is characterized by the presence of intraepidermal and dermal nests of malignant epithelial cells. It may recur after excision and metastasize to the lymph nodes and less frequently to distal anatomic sites.


endolymphatic sac tumor

description: An aggressive epithelial neoplasm arising from the temporal bone. It is characterized by the presence of a papillary pattern, and has been described as an adenoma or carcinoma in the literature. There is disagreement regarding its relationship to endolymphatic sac tumor.


endometrial clear cell adenocarcinoma

description: A clear cell adenocarcinoma that involves the endometrium.


endometrial endometrioid adenocarcinoma

description: A primary endometrial adenocarcinoma composed of neoplastic cells that form complex glandular patterns associated with budding and branching of the neoplastic glands. The neoplastic glands resemble those of the normal endometrium and may or may not be associated with sheet-like proliferation of malignant cells. Endometrioid adenocarcinoma is the most commonly seen morphologic variant of endometrial adenocarcinoma.


endometrial hyperplasia without atypia

description: Simple or complex endometrial hyperplasia characterized by the absence of epithelial atypia.


endometrial polyp

description: A benign nodular lesion protruding above the surface of the endometrium. It is composed of a fibrous stroma that contains thick-walled blood vessels and dilated endometrial glands. Polypectomy is the treatment of choice. Only few cases with recurrence have been reported.


endometrial serous adenocarcinoma

description: A high grade, aggressive adenocarcinoma arising from the endometrium. It is characterized by the presence of complex papillary patterns with cellular budding. Atypical mitoses, necrosis, and psammoma bodies may be present. It is classified as type II endometrial carcinoma and it is not associated with endometrial hyperplasia. It tends to invade deeply into the myometrium and spreads into the lymphatic vessels. Patients frequently present with spread of the tumor beyond the uterus at the time of diagnosis. The prognosis is usually poor.


endometrial small cell carcinoma

description: A primary carcinoma of the endometrium that is similar to the small cell carcinoma of the lung, histologically.


endometrial squamous cell carcinoma

description: A primary carcinoma of the endometrium characterized by the presence of malignant squamous cells.


endometrial undifferentiated carcinoma

description: A primary carcinoma of the endometrium characterized by the presence of malignant cells that lack evidence of differentiation.


epithelioid cell uveal melanoma

description: A uveal melanoma characterized by the presence of malignant large epithelioid melanocytes.


ethmoid sinus adenoid cystic carcinoma

description: An adenoid cystic carcinoma that affects the ethmoid sinus.


name: extrahepatic bile duct adenosquamous carcinoma

description: A carcinoma that arises from the extrahepatic bile ducts. It is characterized by the presence of glandular and squamous malignant epithelial components.


name: extrahepatic bile duct squamous cell carcinoma

description: A carcinoma that arises from the extrahepatic bile ducts. It is composed entirely by malignant squamous epithelial cells.


fallopian tube carcinoma

description: A carcinoma that arises from epithelial cells of the fallopian tube.


fallopian tube carcinosarcoma

description: A carcinosarcoma that arises from the fallopian tube. It usually affects postmenopausal women and presents with abdominal pain, abdominal distension or genital bleeding. The prognosis is usually poor.


fallopian tube serous adenocarcinoma

description: A serous adenocarcinoma that arises from the fallopian tube. It is usually a high grade invasive adenocarcinoma.


fibroblastic neoplasm

description: A benign, intermediate, or malignant mesenchymal neoplasm characterized by the presence of neoplastic fibroblasts.


fibrolamellar hepatocellular carcinoma

description: A distinctive type of liver cell carcinoma that arises in non-cirrhotic livers and is seen predominantly in young patients. The tumor cells are polygonal and deeply eosinophilic, and are embedded in a fibrous stroma. The prognosis is similar to classical hepatocellular carcinoma that arises in non-cirrhotic livers, and better than hepatocellular carcinoma that arises in cirrhotic livers.


fibrous hamartoma of infancy

description: A poorly circumscribed neoplasm arising from the soft tissues in infants. It is characterized by the presence of bland fibroblastic spindle cells, collagenous stroma formation, primitive mesenchymal round cells, and mature fat cells. These components combined form a distinct organoid pattern.


flat urothelial hyperplasia

description: A type of hyperplasia that is characterized by a marked thickening of the urinary tract epithelium. There is no evidence of cytologic atypia. -- 2003


floor of mouth mucoepidermoid carcinoma

description: A mucoepidermoid carcinoma of the oral cavity that arises from the floor of the mouth.


name: follicular variant thyroid gland papillary carcinoma

description: A nonencapsulated variant of papillary carcinoma of the thyroid gland characterized by the predominance of follicular structures. The malignant follicular cells display the nuclear features that characterize the papillary adenocarcinomas of the thyroid gland.


gallbladder adenocarcinoma

description: A carcinoma that arises from glandular epithelial cells of the gall bladder.


gallbladder adenoma

description: A polypoid epithelial neoplasm that arises from the gallbladder. According to the neoplastic growth pattern, it is classified as tubular, tubulopapillary, or papillary.


gallbladder adenosquamous carcinoma

description: A carcinoma that arises from the gallbladder. It is characterized by the presence of glandular and squamous malignant epithelial components.


name: gallbladder biliary intraepithelial neoplasia

description: A neoplastic, non-invasive lesion that affects the gallbladder epithelium. It is characterized by the presence of atypical epithelial cells with an increased nuclear/cytoplasmic ratio, nuclear hyperchromasia, and loss of nuclear polarity.


name: gallbladder small cell neuroendocrine carcinoma

description: An aggressive, high-grade and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the gallbladder. It is characterized by the presence of malignant small cells.


gallbladder squamous cell carcinoma

description: A carcinoma that arises from the gallbladder. It is composed entirely by malignant squamous epithelial cells.


gastric adenoma

description: A neoplastic polyp that arises from the stomach. This category includes intestinal-type adenomatous polyps, gastric-type adenomas, and fundic gland polyps.


gastric choriocarcinoma

description: A malignant germ cell tumor that arises from the stomach. It is characterized by the presence of syncytiotrophoblast and cytotrophoblast cellular components. It is often associated with lymph node and hematogenous metastases.


gastric diffuse large B-cell lymphoma

description: An extranodal diffuse large B-cell lymphoma that arises from the stomach with the bulk of the mass located in the stomach.


gastric hamartomatous polyp

description: A non-neoplastic polyp that arises from the stomach and is characterized by the presence of connective tissue stroma overgrowth and cystic formations.


gastric mantle cell lymphoma

description: A mantle cell lymphoma that affects the stomach. It may arise as a solitary mass or it may be a component of multifocal lymphomatous polyposis of the gastrointestinal tract. It usually has an aggressive clinical course.


name: gastric mucosa-associated lymphoid tissue lymphoma

description: A low grade, indolent B-cell lymphoma, usually associated with Helicobacter pylori infection. Morphologically it is characterized by a dense mucosal atypical lymphocytic (centrocyte-like cell) infiltrate with often prominent lymphoepithelial lesions and plasmacytic differentiation. Approximately 40% of gastric MALT lymphomas carry the t(11;18)(q21;q21). Such cases are resistant to Helicobacter pylori therapy.


gastric neuroendocrine tumor G1

description: A well differentiated, low grade neuroendocrine tumor (carcinoid tumor) that arises from the stomach. The vast majority of cases arise from the corpus-fundus region. The mitotic count is less than 2 per 10 HPF and/or the Ki67 index is equal to or less than 2 percent. It may be associated with autoimmune chronic atrophic gastritis, multiple endocrine neoplasia type 1, or it may be sporadic.


gastric papillary adenocarcinoma

description: A variant of gastric adenocarcinoma with exophytic growth and elongated finger-like processes lined by cylindrical or cuboidal cells supported by fibrovascular connective tissue cores.


name: gastric small cell neuroendocrine carcinoma

description: An aggressive, high-grade and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the stomach. It is characterized by the presence of malignant small cells.


gastric squamous cell carcinoma

description: A rare carcinoma of the stomach resembling squamous cell carcinomas arising elsewhere in the body.


gastrointestinal hamartoma

description: A non-neoplastic, hamartomatous polyp that arises from the stomach, small intestine, and large intestine. This group includes the juvenile polyps and Peutz-Jeghers polyps.


giant cell tumor of soft tissue

description: A painless, well circumscribed tumor arising in soft tissue, usually of the upper and lower extremities. Morphologically, it is characterized by a multinodular growth pattern. The cellular infiltrate is composed of mononuclear round or oval cells and multinucleated osteoclast-like giant cells, in a rich vascular stroma. It rarely metastasizes.


gonadal teratoma

description: A teratoma that arises from the testis or ovary.


name: grade III prostatic intraepithelial neoplasia

description: High grade prostatic intraepithelial neoplasia characterized by the presence of severe architectural and cytologic abnormalities.


granular cell tumor

description: An unusual benign or malignant neoplasm characterized by the presence of neoplastic large polygonal cells with granular, eosinophilic cytoplasm which contains abundant lysosomes. It was originally thought to be a tumor originating from muscle cells and was named granular cell myoblastoma. Subsequent studies have suggested a derivation from Schwann cells. It affects females more often than males and it usually presents as a solitary mass. A minority of patients have multiple tumors. It can arise from many anatomic sites including the posterior pituitary gland, skin, oral cavity, esophagus, stomach, heart, mediastinum, and breast.


granulocytic sarcoma

description: A tumor mass composed of myeloblasts, neutrophils and neutrophil precursors. Granulocytic sarcoma is the most common type of myeloid sarcoma. (WHO, 2001)


name: growth hormone-producing pituitary gland adenoma

description: An adenoma of the anterior lobe of the pituitary gland that produces growth hormone. The vast majority of cases are hormonally functioning and are associated with either gigantism or acromegaly.


head and neck paraganglioma

description: A benign or malignant extra-adrenal paraganglioma arising from paraganglia in the head and neck. Representative examples include the carotid body and jugulotympanic paragangliomas.


hepatic granuloma

description: A granuloma located in the liver.


hepatoid adenocarcinoma

description: An adenocarcinoma with morphologic characteristics similar to hepatocellular carcinoma, arising from an anatomic site other than the liver.


HER2 positive breast carcinoma

description: A biologic subset of breast carcinoma defined by high expression of HER2, GRB7, and TRAP100, and by lack of expression of estrogen receptor (ER).


hidradenocarcinoma

description: A carcinoma with apocrine and less often eccrine differentiation, arising from the sweat glands. It usually presents as a solitary slow growing nodule in the dermis or subcutaneous tissues. It is characterized by a nodular growth pattern and it is often associated with necrotic changes.


high grade surface osteosarcoma

description: A usually aggressive high grade malignant bone-forming mesenchymal neoplasm arising from the surface of the bone.


histiocytic and dendritic cell neoplasm

description: Rare tumors that affect the hematopoietic and lymphoid tissues. The cells of origin are the histiocytes and accessory cells. They can occur at any age and show no significant variations in geographical distribution. This category includes the histiocytic sarcoma, Langerhans cell histiocytosis, Langerhans cell sarcoma, interdigitading dendritic cell sarcoma/tumor, follicular dendritic cell sarcoma/tumor, and dendritic cell sarcoma, not otherwise specified. (WHO, 2001)


hydatidiform mole

description: A gestational trophoblastic disorder characterized by marked enlargement of the chorionic villi, hyperplasia of the villous trophoblastic cells and hydropic changes.


hyperplastic polyp

description: A polyp found mainly in the stomach and colon. Microscopically, it is characterized by elongated, serrated crypts lined by proliferative epithelium. Hyperplastic polyps are traditionally considered non-neoplastic, but ras mutation is common, clonality has been demonstrated and biochemical abnormalities and epidemiological associations that occur in colorectal adenomas and carcinomas have been found (WHO Tumors of the Digestive System, 2000).


ileal neuroendocrine tumor G1

description: A well differentiated, low grade neuroendocrine tumor (carcinoid tumor) that arises from the ileum. The mitotic count is less than 2 per 10 HPF and/or the Ki67 index is equal to or less than 2 percent.


intestinal type adenocarcinoma

description: An adenocarcinoma arising from epithelium which has undergone intestinal metaplasia. Representative examples include gastric, gallbladder, and ampulla of Vater intestinal type adenocarcinomas.


intimal sarcoma

description: A malignant neoplasm arising from the large blood vessels. It is characterized by the presence of tumor cells that grow within the lumen of the blood vessels. The intraluminal tumor growth may result in vascular obstruction and spread of tumor emboli to peripheral organs. The prognosis is usually poor.


invasive breast carcinoma

description: A carcinoma that infiltrates the breast parenchyma. The vast majority are adenocarcinomas arising from the terminal ductal lobular unit (TDLU). Often, the invasive adenocarcinoma co-exists with ductal or lobular carcinoma in situ. It is the most common carcinoma affecting women.


jejunal neuroendocrine tumor G1

description: A well differentiated, low grade neuroendocrine tumor (carcinoid tumor) that arises from the jejunum. The mitotic count is less than 2 per 10 HPF and/or the Ki67 index is equal to or less than 2 percent.


juvenile polyp

description: A non-neoplastic hamartomatous polyp that arises from the stomach and intestinal tract. It is characterized by the presence of tortuous and cystically dilated glands, edematous changes, and inflammation.


kidney medullary carcinoma

description: A type of renal carcinoma affecting mostly young African-Americans. It is located in the medulla of the kidney, and follows an aggressive clinical course. Most reported cases have shown metastatic disease at the time of diagnosis.


lacrimal gland adenoid cystic carcinoma

description: A adenoid cystic carcinoma that involves the lacrimal gland.


laryngeal adenoid cystic carcinoma

description: A rare adenoid cystic carcinoma of the larynx. It usually arises from the supraglottic or subglottic area. It is characterized by slow progression and late distant metastases.


laryngeal small cell carcinoma

description: A rare carcinoma that arises from the larynx. It is characterized by the presence of small neuroendocrine cells. It metastasizes early and has an aggressive clinical course.


Leydig cell tumor

description: A sex cord-stromal tumor occurring in the testis and rarely in the ovary. It is predominantly or completely composed of Leydig cells which may contain crystals of Reinke. In males it usually presents as a painless testicular enlargement and it may be associated with gynecomastia and decreased libido. The majority of the cases have a benign clinical course. Approximately 10% of the cases have a malignant clinical course and metastasize. In females it may be associated with androgenic manifestations and it follows a benign clinical course.


liver cavernous hemangioma

description: A hemangioma with cavernous vascular spaces arising from the liver. It is the most frequent benign tumor of the liver and usually affects young females.


liver diffuse large B-cell lymphoma

description: A rare diffuse large B-cell lymphoma that arises from the liver and the bulk of the tumor is located in the liver.


lobular breast carcinoma in situ

description: A non-invasive adenocarcinoma of the breast characterized by a proliferation of monomorphic cells completely filling the lumina. The overall lobular architecture is preserved. It is frequently multifocal (90% in some series) and bilateral. It seldom becomes invasive; however there is an increased risk of infiltrating ductal adenocarcinoma.


low grade central osteosarcoma

description: A low grade osteosarcoma arising from the medullary portion of the bone. It affects the long bones and is characterized by the presence of fibroblastic stroma and osteoid production. Pain and swelling are the usual sign and symptom. The prognosis is more favorable than conventional osteosarcoma.


low grade fibromyxoid sarcoma

description: A low grade, late-metastasizing variant of fibrosarcoma characterized by alternating fibrous and myxoid areas and a whorling growth pattern. The neoplastic cells have a spindle morphology, and lack hyperchromasia or significant nuclear atypia. Approximately 40% of cases show the focal presence of collagen rosettes. A t(7;16)(q33;p11) translocation has been identified in the majority of cases, associated with the presence of FUS-CREB3L2 fusion protein. Rare cases carry the t(11;16)(p11;p11) translocation which is associated with the presence of the FUS-CREB3L1 fusion protein.


name: low grade fibromyxoid sarcoma with giant collagen rosettes

description: A low grade fibromyxoid sarcoma characterized by the presence of prominent collagen rosettes.


name: low grade vulvar intraepithelial neoplasia

description: An intraepithelial lesion of the vulvar squamous epithelium that represents the clinical and morphological manifestation of a productive HPV infection. Low grade refers to the associated low risk of concurrent or future cancer. (WHO, 2014)


lung giant cell carcinoma

description: A morphologic variant of lung sarcomatoid carcinoma characterized by the presence of mononuclear and multinucleated pleomorphic neoplastic giant cells that lack cohesion.


lung inflammatory myofibroblastic tumor

description: An intermediate fibroblastic neoplasm arising from the lung. It is characterized by the presence of spindle-shaped fibroblasts and myofibroblasts, and a chronic inflammatory infiltrate composed of eosinophils, lymphocytes and plasma cells.


lung lymphangioleiomyomatosis

description: Lymphangiomyomatosis involving the lungs and local lymph nodes. Patients usually present with chylous pleural effusion. The clinical course is variable. Patients with resectable lesions usually have a favorable clinical outcome. Patients with diffuse lesions usually have a progressive clinical course.


lung papilloma

description: A benign papillary neoplasm that arises endobronchially. It is classified as squamous cell, glandular, or mixed squamous cell and glandular papilloma. Patients usually present with signs and symptoms of bronchial obstruction.


lung sarcomatoid carcinoma

description: A rare, aggressive, poorly differentiated, non-small cell lung carcinoma characterized by the presence of a sarcomatoid component often associated with giant cell differentiation. There is a male to female ratio of 4:1. Clinical symptoms include cough, hemoptysis, chest pain, progressive dyspnea and fever secondary to recurrent pneumonia. Cigarette smoking is a major risk factor.


lung sclerosing hemangioma

description: A benign tumor that arises from the lung. It is characterized by the presence of sclerotic, papillary, solid, and hemorrhagic patterns and hyperplastic type II pneumocytes. Cholesterol clefts, hemosiderin deposition, chronic inflammation, and calcifications may be present. In the majority of cases, it is a solitary and peripheral tumor. Patients are usually asymptomatic.


lung signet ring cell carcinoma

description: A morphologic variant of lung adenocarcinoma characterized by the presence of signet ring cells.


lymphangiosarcoma

description: A malignant neoplasm arising from the endothelial cells of the lymphatic vessels.


lymphoepithelioma-like lung carcinoma

description: A morphologic variant of large cell lung carcinoma characterized by the presence of a syncytial growth pattern, large vesicular nuclei with esophnophilic nucleoi, and dense lymphoplasmacytic infiltration.


major salivary gland carcinoma

description: A carcinoma that arises from the parotid gland, submandibular gland, or sublingual gland.


name: major salivary gland carcinoma ex pleomorphic adenoma

description: A carcinoma that arises from a pleomorphic adenoma in the major salivary glands. It usually originates in the parotid gland. Patients usually present with a history of a long-standing tumor mass which grew rapidly in the past few months. Patients with non-invasive or minimally invasive carcinoma have an excellent prognosis. In cases where there is invasion of the surrounding tissues, the clinical course is aggressive.


name: major salivary gland mucoepidermoid carcinoma

description: A carcinoma that arises from the major salivary glands. It usually arises from the parotid gland. It is the most common primary carcinoma of the salivary glands and usually presents as a firm and painless mass. It is characterized by the presence of epidermoid cells, mucus producing cells, and cells of intermediate type. The majority of cases have a favorable outcome.


malignancy in giant cell tumor of bone

description: A malignant tumor that arises from the bone. It is characterized by the presence of an area of high grade sarcoma in an otherwise typical giant cell tumor (primary malignancy in giant cell tumor), or the presence of sarcoma in which the pre-existing giant cell tumor may or may not be apparent (secondary malignancy in giant cell tumor).


name: malignant adrenal gland pheochromocytoma

description: A pheochromocytoma that metastasizes to other anatomic sites. Common sites of metastasis include lymph nodes, bones, liver, and lung. Morphologic features associated with malignant pheochromocytomas include: atypical mitotic figures, capsular and vascular invasion, tumor cell necrosis, and high mitotic activity.


malignant germ cell tumor

description: A gonadal or extragonadal malignant neoplasm that arises from germ cells. Representative examples include embryonal carcinoma, yolk sac tumor, and seminoma.


malignant jugulotympanic paraganglioma

description: A jugulotympanic paraganglioma that metastasizes to other anatomic sites.


malignant mesothelioma

description: A malignant neoplasm of the pleura or peritoneum, arising from mesothelial cells. It is associated with exposure to asbestos.


pleural cancer

description: A primary or metastatic malignant neoplasm affecting the pleura. A representative example of primary malignant pleural neoplasm is the malignant pleural mesothelioma. A representative example of metastatic malignant neoplasm to the pleura is metastatic carcinoma that has spread to the pleura from another anatomic site.


malignant urinary system neoplasm

description: A primary or metastatic malignant tumor involving the urinary system. Common tumor types include carcinomas, lymphomas, and sarcomas.


name: maxillary sinus adenoid cystic carcinoma

description: An adenoid cystic carcinoma that arises from the maxillary sinus. It usually has an aggressive clinical course.


mediastinal malignant germ cell tumor

description: An extragonadal malignant germ cell tumor that arises from the mediastinum. This category includes seminoma, embryonal carcinoma, yolk sac tumor, choriocarcinoma, mixed germ cell tumors, and immature malignant teratoma.


name: medullomyoblastoma with myogenic differentiation

description: A rare malignant embryonal neoplasm arising from the cerebellum. It is characterized by the morphologic features of a medulloblastoma and the presence of a striated muscle component. Its clinical behavior is similar to medulloblastoma.


metanephric adenoma

description: A benign, well-circumscribed renal cortical neoplasm affecting females more often than males. Polycythemia has been reported in twelve-percent of patients.


micropapillary serous carcinoma

description: An adenocarcinoma characterized by the presence of complex micropapillary structures covered by round and cuboidal cells with a high nuclear to cytoplasmic ratio.


middle ear squamous cell carcinoma

description: A rare squamous cell carcinoma that arises from the middle ear.


minor salivary gland adenocarcinoma

description: An adenocarcinoma that arises from the minor salivary glands.


name: mixed lobular and ductal breast carcinoma

description: A breast carcinoma characterized by the presence of a lobular and a ductal component. The ductal component comprises less than 50 percent of the tumor.


name: mixed somatotroph-lactotroph pituitary gland adenoma

description: An infrequent pituitary gland adenoma composed of an admixture of acidophilic and chromophobic cells that produce growth hormone and prolactin respectively. Unlike mammosomatotroph adenomas, these two hormones are not localized in the same cell by immunohistochemistry.


mucinous gastric adenocarcinoma

description: A variant of gastric adenocarcinoma with more than half of the tumor containing extracellular mucinous pools.


description: A category of clonal hematopoietic disorders that have both myelodysplastic and myeloproliferative features at the time of initial presentation.


myofibroma

description: A benign, localized, nodular and well-circumscribed neoplasm usually seen as a congenital neoplasm or in the first year of life. It is characterized by a biphasic growth pattern and is composed of small, undifferentiated mesenchymal cells associated with branching thin-walled vessels and more mature neoplastic spindle cells with abundant eosinophilic cytoplasm in a collagenous stroma.


nabothian cyst

description: A benign, mucus-filled cervical cyst that occurs when mucus-secreting columnar epithelial cells are covered with squamous epithelium.


nasal cavity polyp

description: A soft and painless polypoid mass that arises from the mucosa in the nasal cavity. It is usually the result of an inflammatory process. It may recur following surgical resection.


neuroblastic tumor

description: A group of nervous system tumors which display neuronal differentiation. It includes tumors that are composed of immature round cells and tumors that display advanced differentiation and the formation of ganglion cells.


neurothekeoma

description: A benign neoplasm arising from nerve sheaths. It is characterized by the presence of a myxoid stroma.


non-cutaneous melanoma

description: Melanoma is a malignant tumor of melanocytes, cells that are derived from the neural crest. Although most melanomas arise in the skin, they also may arise from mucosal surfaces or at other sites to which neural crest cells migrate. (PDQ)


non-functioning adrenal cortex adenoma

description: An adenoma of the adrenal cortex characterized by the absence of a hormonal syndrome or symptoms suggestive of adrenal disease.


non-neoplastic bile duct disorder

description: A non-neoplastic disorder that affects the intrahepatic or extrahepatic bile ducts. Representative examples include cholangitis and biliary atresia.


non-seminomatous lesion

description: A group of testicular cancers that begin in the germ cells (cells that give rise to sperm). Nonseminomas are identified by the type of cell in which they begin and include embryonal carcinoma, teratoma, choriocarcinoma, and yolk sac carcinoma.


name: normal breast-like subtype of breast carcinoma

description: A biologic subset of breast carcinoma defined by high expression of many genes expressed by adipose and other non-epithelial tissues.


ocular melanoma

description: A melanoma that arises from the structures of the eye or ocular adnexa.


name: ocular melanoma with extraocular extension

description: A melanoma arising from and extending beyond the structures of the eye.


ocular sebaceous carcinoma

description: Ocular sebaceous carcinoma is a rare condition and accounts for 1% to 5.5% of eyelid malignancies and is the third most common eyelid malignancy after basal cell and squamous cell carcinoma. It usually affects elderly women, has a high rate of local recurrence, and a tendency to regional and distant metastases.


odontogenic cyst

description: A cyst in the jaw that arises from tissues of tooth development.


olfactory neuroblastoma

description: An olfactory neuroblastoma arising in the paranasal sinus.


ossifying fibromyxoid tumor

description: A rare soft tissue tumor of uncertain lineage characterized by the presence of neoplastic spindle to round cells forming cords in a fibromyxoid stroma. The lesions are associated with the formation of metaplastic bone. Most patients present with painless subcutaneous masses. Recurrences have been reported in a minority of patients.


ovarian endometrioid adenocarcinoma

description: An endometrioid adenocarcinoma arising from the ovary. It comprises 10% to 25% of all primary ovarian carcinomas. Grossly, endometrioid carcinoma may present as a cystic or solid mass. Microscopically, the tumor greatly resembles the appearance of the ordinary type of endometrial adenocarcinoma. As a group, endometrioid carcinoma has a prognosis twice as good as that of serous or mucinous carcinoma.


name: ovarian endometrioid adenocarcinoma with squamous differentiation

description: An endometrioid adenocarcinoma that arises from the ovary and exhibits squamous differentiation. The squamous cell component often has a cytologically benign appearance.


ovarian endometriosis

description: A non-neoplastic disorder characterized by the growth of endometrial tissue in the ovaries. It results in the development of blood filled ovarian cysts (chocolate cysts), and creation of scars and adhesions.


ovarian microcystic stromal tumor

description: A benign, unilateral tumor that arises from the ovary and is characterized by the presence of conspicuous microcystic changes, cellular areas, and a fibrous stroma.


ovarian serous adenofibroma

description: A benign neoplasm of the ovary characterized by the presence of glands with serous epithelial cells in a fibrotic stroma.


ovarian transitional cell carcinoma

description: A carcinoma that arises from the ovary and is characterized by the presence of malignant epithelial cells that resemble malignant urothelial cells. There is no morphologic evidence of a benign or borderline Brenner tumor component present.


ovarian yolk sac tumor

description: A usually rapidly growing malignant germ cell tumor arising from the ovary. It usually occurs in children and adolescents. Signs and symptoms include abdominal pain and a large abdominal or pelvic mass. The serum alpha-fetoprotein is almost always elevated preoperatively. Morphologically, there is marked heterogeneity due to numerous patterns of differentiation coexisting in the same tumor. The most common pattern is reticular.


palmar fibromatosis

description: A superficial fibromatosis arising from the soft tissue of the palm. It is characterized by the presence of spindle-shaped fibroblasts, and an infiltrative growth pattern. It predominantly affects adult males.


pancreatic acinar cell carcinoma

description: An adenocarcinoma arising from the pancreas. It is characterized by the presence of relatively uniform malignant cells which form acinar patterns. It usually occurs during adulthood. Signs and symptoms include abdominal pain, weight loss, nausea, and diarrhea. It may metastasize to regional lymph nodes and the liver. A minority of patients develop lipase hypersecretion syndrome. This syndrome may be seen in patients with liver metastases and it is characterized by excessive secretion of lipase in the serum, polyarthralgia, and subcutaneous fat necrosis.


name: pancreatic large cell neuroendocrine carcinoma

description: An aggressive, high-grade and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the pancreas. It is characterized by the presence of malignant large cells.


name: pancreatic small cell neuroendocrine carcinoma

description: An aggressive, high-grade and poorly differentiated carcinoma with neuroendocrine differentiation that arises from the pancreas. It is characterized by the presence of malignant small cells.


papillary cystic neoplasm

description: A benign, malignant, or borderline neoplasm characterized by the presence of papillary mucinous, serous, or clear cell structures and cystic structures.


papillary transitional cell carcinoma

description: A non-invasive or invasive transitional cell carcinoma characterized by a papillary growth pattern. It may occur in the bladder or the renal pelvis.


parachordoma

description: A rare, usually benign myoepithelial tumor characterized by the presence of epithelioid, often vacuolated neoplastic cells. Most patients present with painless swelling in the subcutaneous or subfascial soft tissues of the extremities.


name: paranasal sinus adenoid cystic carcinoma

description: A rare adenoid cystic carcinoma that arises from the paranasal sinuses. It usually has an aggressive clinical course characterized by high recurrence rates and distant metastases.


paranasal sinus Schneiderian papilloma

description: A papilloma that arises from the ciliated respiratory mucosa that lines the paranasal sinuses. It is classified as inverted papilloma and oncocytic papilloma.


parathyroid hyperplasia

description: A hyperplasia that involves the parathyroid gland.


parotid gland acinic cell carcinoma

description: An adenocarcinoma with serous acinar cell differentiation that arises from the parotid gland. Patients usually present with a slow growing mass in the parotid area.


parotid gland adenoid cystic carcinoma

description: An aggressive carcinoma that arises from the parotid gland. It is characterized by the presence of malignant epithelial and myoepithelial cells forming cribriform, tubular, and solid patterns. It usually presents as a slow growing mass. Patients develop pain because of the tendency of these carcinomas to invade perineural tissues.


name: parotid gland carcinoma ex pleomorphic adenoma

description: A carcinoma that arises from a pleomorphic adenoma in the parotid gland. Patients usually present with a history of a long-standing tumor mass which grew rapidly in the past few months. Patients with non-invasive or minimally invasive carcinoma have an excellent prognosis. In cases where there is invasion of the surrounding tissues, the clinical course is aggressive.


parotid gland squamous cell carcinoma

description: An invasive squamous cell carcinoma that arises from the parotid gland. It usually affects elderly patients and presents as a rapidly enlarging tumor mass, often associated with pain.


name: neoplasm with perivascular epithelioid cell differentiation

description: A soft tissue neoplasm composed of perivascular epithelioid cells. Representative examples include angiomyolipoma, clear cell-sugar-tumor of the lung, and lymphangioleiomyomatosis.


penile carcinoma

description: A carcinoma that arises from epithelial cells of the penis


peritoneal mesothelioma

description: A benign or malignant mesothelial neoplasm that arises from the peritoneum.


peritoneal multicystic mesothelioma

description: A cystic mesothelioma that arises from the peritoneum and usually affects young to middle aged females. Grossly, it presents as a large multiloculated tumor mass, usually in the pelvic peritoneum. Histologically it is characterized by the presence of multiple cysts that are lined by one or more layers of mesothelial cells that do not show atypia. Patients usually present with abdominal or pelvic mass and pain. The clinical course is indolent. The tumor may recur, but transformation to diffuse malignant mesothelioma is rare.


name: peritoneal well differentiated papillary mesothelioma

description: A localized or multifocal mesothelioma arising from the peritoneum. It predominantly occurs in women. It is characterized by the formation of papillae, covered by a single layer of blunt mesothelial cells. Mitotic figures are not present. There is no evidence of severe cytologic atypia. It has a relatively favorable clinical outcome, compared to diffuse malignant mesothelioma.


Peutz-Jeghers polyp

description: A hamartomatous polyp that occurs in the stomach, small and large intestines, and rarely within the esophagus, nasopharynx and the urinary tract. The Peutz-Jeghers polyps are grossly lobulated and dark. Microscopically, they have a central core of smooth muscle covered by mucosa. The smooth muscle shows tree-like branching. The question of whether or not the Peutz-Jeghers polyp is precancerous is a matter of controversy. The loss of heterozygosity on chromosome 19p (where the responsible gene LKB1 is located) suggests that the increased risk of malignancy may be due to malignant transformation from hamartoma to adenocarcinoma. --2002


Peutz-Jeghers polyp of the stomach

description: A non-neoplastic polyp that arises from the stomach and is characterized by the presence of smooth muscle branching bands, and hyperplasia with cystic dilatation of the foveolar epithelium.


pharyngeal adenoid cystic carcinoma

description: An adenoid cystic carcinoma that arises from the pharynx.


phosphaturic mesenchymal tumor

description: An extremely rare, benign or malignant mesenchymal tumor arising from the soft tissues or bones. It is a distinctive tumor, which usually displays the following morphologic characteristics: low cellularity, myxoid changes, presence of spindled cells and osteoclasts, hemangiopericytoma-like vessels, hemorrhage, and osteoid-like matrix. It is associated with the presence of a paraneoplastic syndrome called osteogenic osteomalacia. This syndrome usually precedes the appearance of the tumor, and it is characterized by phosphaturia, hypophosphatemia, normal serum calcium levels, and decreased levels of 1,25-dihydroxyvitamin D3. Patients present with bone and muscle pain, severe muscle weakness, fractures, gait disturbances, skeletal deformity, height loss, and slow growth. The metabolic disturbances improve or completely disappear after the complete resection of the tumor.


name: pineal parenchymal tumor of intermediate differentiation

description: A WHO grade II or III pineal parenchymal neoplasm of intermediate-grade malignancy, affecting all ages. It is composed of diffuse sheets or large lobules of uniform cells with mild to moderate nuclear atypia and low to moderate level mitotic activity. (Adapted from WHO)


pituicytoma

description: An extremely rare, WHO grade I, circumscribed and slow-growing tumor that arises from the neurohypophysis or infundibulum and described in adults. It is characterized by the presence of elongated, spindle-shaped neoplastic glial cells that form storiform patterns or interlacing fascicular arrangements. Signs and symptoms include visual disturbances, headache, amenorrhea, and decreased libido.


pituitary gland adenoma

description: A non-metastasizing tumor that arises from the adenohypophysial cells of the anterior lobe of the pituitary gland. The tumor can be hormonally functioning or not. The diagnosis can be based on imaging studies and/or radioimmunoassays. Due to its location in the sella turcica, expansion of the tumor mass can impinge on the optic chiasm or involve the temporal lobe, third ventricle and posterior fossa A frequently associated physical finding is bitemporal hemianopsia which may progress to further visual loss.


placental choriocarcinoma

description: Choriocarcinoma that develops in the placenta. It is the rarest form of gestational choriocarcinoma. Metastases to the mother and infant may occur.


placental hemangioma

description: A hemangioma arising from the fetal blood vessels in the placental villi.


pleural biphasic mesothelioma

description: Malignant mesothelioma that arises from the pleura. It is characterized by the presence of epithelioid and sarcomatoid components, with each component representing at least 10% of the tumor.


pleural epithelioid mesothelioma

description: Malignant mesothelioma that arises from the pleura and is characterized by the presence of cells with epithelioid morphology. The epithelioid cells usually have eosinophilic cytoplasm, bland nuclei, and form tubulopapillary, microglandular, or sheet-like patterns.


pleural sarcomatoid mesothelioma

description: Malignant mesothelioma that arises from the pleura and is characterized by the presence of spindle-shaped cells forming fascicles, or that are distributed haphazardly resembling a sarcoma.


plexiform ameloblastoma

description: A histologic variant of solid/multicystic ameloblastoma characterized by the presence of basal cells forming anastomosing strands and cords in a delicate stroma.


name: poorly differentiated thyroid gland carcinoma

description: An adenocarcinoma arising from the thyroid gland showing only limited evidence of follicular cell differentiation. Microscopically, the adenocarcinoma cells are arranged in insular, solid, and trabecular patterns. There is associated necrosis, and vascular invasion. The prognosis depends on the tumor stage, complete or partial surgical removal of the tumor, and the degree of response to radioactive iodine therapy (adapted from WHO Tumors of Endocrine Organs, IARC Press, Lyon 2004)


name: primary cutaneous diffuse large B-cell lymphoma, Leg type

description: An aggressive primary cutaneous B-cell lymphoma, usually involving the lower leg. It is composed of a generally monotonous proliferation of immunoblasts, or less frequently centroblasts, with few admixed reactive cells. This type of lymphoma occurs most often in elderly women who present with rapidly growing tumors, usually on one or both legs. Dissemination to extracutaneous sites is frequent. Treatment with combination chemotherapy is usually required.


name: primary intraosseous squamous cell carcinoma

description: A squamous cell carcinoma that arises centrally from the jaw. It derives from odontogenic epithelial remnants. It includes solid type squamous cell carcinoma, squamous cell carcinoma that arises from an odontogenic cyst, and squamous cell carcinoma that derives from a keratocystic odontogenic tumor.


name: primary peritoneal serous adenocarcinoma

description: A rare, serous adenocarcinoma that diffusely involves the pelvic peritoneum seen predominantly in elderly postmenopausal women. Exclusion of serous carcinoma arising from the ovary and fimbrial end of fallopian tube is required to diagnose the above entity.


name: primary pulmonary diffuse large B-cell lymphoma

description: A diffuse large B-cell lymphoma that is localized to the lungs at the time of presentation. Signs and symptoms include cough, dyspnea, and hemoptysis.


name: prolactin-producing pituitary gland carcinoma

description: A rare, hormonally functioning or non-functioning pituitary gland adenocarcinoma that produces prolactin.


prostate rhabdomyosarcoma

description: A malignant mesenchymal neoplasm with skeletal muscle differentiation affecting the prostate.


prostate small cell carcinoma

description: A neuroendocrine carcinoma of the prostate gland with unfavorable prognosis, composed of small cells containing neurosecretory granules. Approximately half of the cases show a mixture of small cells and adenocarcinoma cells.


pyloric gland adenoma

description: A rare neoplastic polyp that arises from the stomach. It is characterized by the presence of gastric epithelial differentiation and pyloric gland-type tubular structures, which are closely packed.


rectal hyperplastic polyp

description: A serrated polypoid lesion that arises in the rectum. It rarely produces symptoms. This group includes goblet cell rich, mucin poor, and microvesicular hyperplastic polyps.


rectal traditional serrated adenoma

description: An adenoma that arises from the rectum. It is characterized by prominent serration of the glands and the presence of generalized low-grade dysplasia.


rectal tubular adenoma

description: A usually polypoid neoplasm that arises from the glandular epithelium of the rectal mucosa. It is characterized by a tubular architectural pattern. The neoplastic glandular cells have dysplastic features.


rectal tubulovillous adenoma

description: A neoplasm that arises from the glandular epithelium of the rectal mucosa. It is characterized by tubular and villous architectural patterns. The neoplastic glandular cells have dysplastic features.


rectal villous adenoma

description: A neoplasm that arises from the glandular epithelium of the rectal mucosa. It is characterized by a villous architectural pattern. The neoplastic glandular cells have dysplastic features.


name: renal cell carcinoma associated with Xp11.2 translocations/TFE3 gene fusions

description: A group of kidney carcinomas characterized by the presence of different translocations involving the chromosome Xp11.2. These translocations result in the creation of gene fusions involving the TFE3 gene. Patients are usually children and young adults. Morphologically, the malignant epithelial cells form papillary patterns.


name: retroperitoneal inflammatory myofibroblastic tumor

description: A multinodular intermediate fibroblastic neoplasm arising from the retroperitoneum. It is characterized by the presence of spindle-shaped fibroblasts and myofibroblasts, and a chronic inflammatory infiltrate composed of eosinophils, lymphocytes and plasma cells.


salivary gland acinic cell carcinoma

description: A carcinoma of the salivary gland characterized by serous acinar cell differentiation. The vast majority of cases occur in the parotid gland. It usually presents as a slowly enlarging mass. A minority of patients experience pain. It may recur or metastasize. Multiple recurrences and metastasis to cervical lymph nodes are usually associated with a poor prognosis.


salivary gland adenosquamous carcinoma

description: A rare, aggressive carcinoma that arises from the salivary glands. It is characterized by the presence of a squamous and a glandular epithelial component.


name: salivary gland basal cell adenocarcinoma

description: A rare adenocarcinoma of the major and minor salivary glands, originating from basaloid, myoepithelial and ductal cells. While morphologically resembling basal cell carcinomas, it is a distinct entity. The tumor is not encapsulated, may invade locally, and less frequently may metastasize. It usually occurs in older patients.


name: salivary gland carcinoma ex pleomorphic adenoma

description: A carcinoma that arises from a pleomorphic adenoma in the salivary glands. It usually originates in the parotid gland. Patients usually present with a history of a long-standing tumor mass which grew rapidly in the past few months. Patients with non-invasive or minimally invasive carcinoma have an excellent prognosis. In cases where there is invasion of the surrounding tissues, the clinical course is aggressive.


salivary gland large cell carcinoma

description: A rare, highly aggressive carcinoma that arises from the salivary gland, predominantly the parotid gland. It is characterized by the presence of large pleomorphic malignant cells with abundant cytoplasm. Patients usually present with a rapidly growing mass.


salivary gland small cell carcinoma

description: An infrequent small cell carcinoma that arises from the salivary glands and is characterized by the presence of a high number of mitotic figures.


sarcomatoid carcinoma

description: A malignant epithelial neoplasm characterized by the presence of spindle cells and anaplastic morphologic features. Giant cells and a sarcomatous component may also be present.


sarcomatoid mesothelioma

description: A diffuse malignant mesothelioma arising from the pleura and less often the peritoneum. It is characterized by the presence of spindle cells. Anaplastic morphologic features and multinucleated malignant cells may also be seen.


name: sex hormone-producing adrenal cortex adenoma

description: A rare adenoma of the adrenal cortex that produces androgens or estrogens.


signet ring cell gastric adenocarcinoma

description: A poorly cohesive gastric adenocarcinoma characterized by malignant cells containing intracytoplasmic mucin.


simple endometrial hyperplasia

description: A proliferation of endometrial cells resulting in glandular enlargement and budding without changes in the basic structure of the endometrium. Epithelial atypia may be present or absent.


sinonasal undifferentiated carcinoma

description: A rare, highly aggressive carcinoma that arises from the sinonasal tract. It is characterized by the presence of small to medium size malignant cells. The prognosis is poor.


name: sinus histiocytosis with massive lymphadenopathy

description: A rare disorder of unknown etiology characterized by distention of the lymph node sinuses and sinusoidal histiocytic infiltration. The histiocytes characteristically contain ingested lymphocytes. Patients present with cervical lymphadenopathy, fever, leukocytosis, and hypergammaglobulinemia. It can affect extranodal sites, including skin, bones, and the respiratory tract. It usually regresses spontaneously.


skin sarcoma

description: A sarcoma that arises from the skin. Representative examples include Kaposi sarcoma, angiosarcoma, lymphangiosarcoma, liposarcoma, and leiomyosarcoma.


small intestinal Burkitt lymphoma

description: A Burkitt lymphoma that arises from the small intestine.


name: small intestinal diffuse large B-cell lymphoma

description: A diffuse large B-cell lymphoma that arises from the small intestine.


name: small intestinal enteropathy-associated T-cell lymphoma

description: An enteropathy-associated T-cell lymphoma arising from the small intestine, most commonly the jejunum or ileum. Patients usually present with abdominal pain, often associated with intestinal perforation. There is often a history of celiac disease. The lymphoma cells are usually medium-sized to large and form an ulcerating mucosal lesion with invasion of the small intestinal wall. Villous atrophy is present in the adjacent small intestinal mucosa. In a minority of cases the lymphoma cells are medium-sized and form a monomorphic infiltrate.


name: small intestinal intraepithelial neoplasia

description: A precancerous neoplastic process that affects the small intestine. It is characterized by low or high grade dysplasia of the mucosal epithelium. There is no evidence of invasion.


name: small intestinal mucosa-associated lymphoid tissue lymphoma

description: A mucosa-associated lymphoid tissue lymphoma (MALT) that arises from the small intestine. The morphologic characteristics are similar to those seen in gastric MALT lymphomas, with the exception of the lymphoepithelial lesions that are less prominent in the small intestine.


small intestinal tubular adenoma

description: A usually polypoid neoplasm that arises from the glandular epithelium of the small intestine. It is characterized by a tubular architectural pattern. The neoplastic glandular cells have dysplastic features.


small intestinal tubulovillous adenoma

description: A neoplasm that arises from the glandular epithelium of the small intestine. It is characterized by tubular and villous architectural patterns. The neoplastic glandular cells have dysplastic features.


soft tissue chondroma

description: A benign neoplasm arising from the extraskeletal soft tissues near tendons and joints. It is a well circumscribed tumor characterized by the presence of chondrocytes, a lobulated hyaline cartilage growth pattern, and in some cases calcification.


soft tissue neoplasm

description: A benign, intermediate, or malignant neoplasm that arises from the soft tissue. The most common types are lipomatous (fatty), vascular, smooth muscle, fibrous, and fibrohistiocytic neoplasms.


name: spinal cord primitive neuroectodermal tumor

description: A central nervous system embryonal tumor, not otherwise specified arising from the spinal cord.


spindle cell melanoma

description: A melanoma characterized by the presence of malignant spindle-shaped melanocytes.


splenic diffuse large B-cell lymphoma

description: A diffuse large B-cell lymphoma occurring in the spleen.


splenic hodgkin lymphoma

description: A rare Hodgkin lymphoma that arises from the spleen.


splenic mantle cell lymphoma

description: A mantle cell lymphoma occurring in the spleen.


stromal predominant kidney Wilms tumor

description: Wilms tumor of the kidney characterized by the predominance of the mesenchymal component.


submandibular gland adenocarcinoma

description: An adenocarcinoma that arises from the submandibular gland. Representative examples include polymorphic low-grade adenocarcinoma and acinic cell carcinoma.


name: submandibular gland adenoid cystic carcinoma

description: An aggressive carcinoma that arises from the submandibular gland. It is characterized by the presence of malignant epithelial and myoepithelial cells forming cribriform, tubular, and solid patterns. It usually presents as a slow growing mass. Patients develop pain because of the tendency of these carcinomas to invade perineural tissues.


synovial chondromatosis

description: Synovial chondromatosis is a type of non-cancerous tumor that arises in the lining of a joint. The knee is most commonly affected, however it can affect any joint. The tumors begin as small nodules of cartilage. These nodules can separate and become loose within the joint. Some tumors may be no larger than a grain of rice. Synovial chondromatosis most commonly occurs in adults ages 20 to 50. Signs and symptoms may include pain, swelling, a decreased range of motion, and locking of the joint. The exact underlying cause of the condition is unknown. Treatment may involve surgery to remove the tumor. Recurrence of the condition is common.


tendon sheath fibroma

description: A small, slow growing, benign neoplasm arising from the tendon sheaths. The tumor is characterized by the presence of spindle-shaped fibroblasts and collagenous stroma formation.


teratoma with malignant transformation

description: A teratoma which is characterized by morphologic transformation to malignancy and an aggressive clinical course. The malignant component most often is sarcomatous or carcinomatous.


testicular embryonal carcinoma

description: A malignant germ cell neoplasm arising from the testis. It is composed of primitive epithelial cells arranged in solid, papillary, and glandular configurations. Most patients present with a testicular mass, which may be associated with pain. More than half of the patients have metastatic disease at diagnosis. The form of treatment following radical orchiectomy is stage dependent.


name: testicular non-seminomatous germ cell tumor

description: A testicular germ cell tumor characterized by the absence of a seminomatous component. It includes embryonal carcinoma, yolk sac tumor, choriocarcinoma, teratoma, and mixed forms.


therapy-related myeloid neoplasm

description: Acute myeloid leukemias, myelodysplastic syndromes, and myelodysplastic/myeloproliferative neoplasms arising as a result of the mutagenic effect of chemotherapy agents and/or radiation that are used for the treatment of neoplastic or non-neoplastic disorders.


thymic carcinoma

description: Thymic carcinoma (TC) is a type of thymic epithelial neoplasm characterized by a high malignant potential.


thymic sarcomatoid carcinoma

description: A rare, usually aggressive, primary thymic carcinoma, characterized by the presence of tumor cells morphologically resembling soft tissue sarcoma.


thymic undifferentiated carcinoma

description: A rare primary thymic carcinoma, characterized by an undifferentiated solid tumor growth, without associated sarcomatoid features.


thymoma

description: A neoplasm arising from the epithelial cells of the thymus. Although thymomas are usually encapsulated tumors, they may invade the capsule and infiltrate the surrounding tissues or even metastasize to distant anatomic sites. The following morphologic subtypes are currently recognized: type A, type B, type AB, metaplastic, micronodular, microscopic, and sclerosing thymoma. Thymomas type B are further subdivided into types B1, B2, and B3. Thymoma type B3 usually has the most aggressive clinical course.


thymoma type B3

description: Also known as well-differentiated thymic carcinoma, atypical thymoma, or epithelial thymoma, this type of thymoma displays morphologic characteristics of a well-differentiated carcinoma. The majority of cases occur in the anterior mediastinum as Masaoka stage II or stage III tumors. It is almost always invasive, it recurs frequently, and metastasizes in approximately 20% of the cases.


thymoma type B1

description: A thymic epithelial neoplasm characterized by the presence of expanded areas which resemble the normal thymic cortex. The neoplastic epithelial cells are small and scant and there is a dense T-lymphocytic component present. Areas of medullary differentiation with or without Hassall's corpuscles are also present. It may be associated with myasthenia gravis, pure red cell aplasia, and hypogammaglobulinemia. It has a low grade malignant potential. The majority of cases occur in the anterior mediastinum as Masaoka stage I tumors. A minority of the cases occur as stage II tumors.


thyroglossal duct cyst

description: A congenital benign cyst arising from the remnants of the thyroglossal duct. It is usually located in the midline of the neck.


name: thyroid gland diffuse large B-cell lymphoma

description: A diffuse large B-cell lymphoma primarily involving the thyroid gland.


thyroid gland mucoepidermoid carcinoma

description: A primary, low grade carcinoma of the thyroid gland composed of groups of squamoid and mucous cells, surrounded by fibrous tissue. Prominent cystic structures may be present. The clinical course is usually indolent.


name: thyroid gland mucosa-associated lymphoid tissue lymphoma

description: An extranodal marginal zone B-cell lymphoma arising from mucosa-associated lymphoid tissue in the thyroid gland. The vast majority of cases are associated with chronic lymphocytic thyroiditis.


name: thyroid gland oncocytic follicular carcinoma

description: A follicular carcinoma of the thyroid gland, characterized by the presence of large cells with eosinophilic granular cytoplasm and pleomorphic nuclei with prominent, eosinophilic nucleoli. The nuclear features that characterize the papillary carcinomas of the thyroid gland are absent.


name: thyroid gland spindle cell tumor with thymus-like differentiation

description: A rare, slow growing, primary carcinoma of the thyroid gland characterized by a lobulated architectural pattern and the presence of a biphasic cellular population composed of spindle epithelial cells and glandular cells. A small number of cases are composed exclusively of spindle epithelial cells or glandular cells.


thyroid gland squamous cell carcinoma

description: A rapidly growing primary carcinoma of the thyroid gland composed of malignant squamous cells. The clinical course is usually aggressive.


name: thyroid gland undifferentiated (anaplastic) carcinoma

description: A primary carcinoma of the thyroid gland composed of undifferentiated cells. The malignant cells demonstrate evidence of epithelial differentiation, either by immunohistochemistry or electron microscopic studies. Microscopically, in the majority of cases there is a mixture of spindle, epithelioid, and giant cells. The vast majority of the patients present with a rapidly enlarging neck mass. The clinical course is usually aggressive.


tibial adamantinoma

description: An adamantinoma arising from the tibia. The tibia is the site which is more frequently involved by adamantinoma (80-90% of cases).


tonsillar squamous cell carcinoma

description: A squamous cell carcinoma that arises from the mucosal lining of the tonsil and tends to metastasize early to the lymph nodes. It predominantly affects middle aged and elderly patients who have a history of alcohol and tobacco use. Patients may present with tonsillar swelling, sore throat, pain radiating to the ipsilateral ear, or a neck mass.


tracheal adenoid cystic carcinoma

description: An adenoid cystic carcinoma that arises from the trachea. It spreads to the submucosal tracheal tissue and to regional lymph nodes.


transitional cell carcinoma

description: A malignant neoplasm arising from the transitional epithelium, usually affecting the urinary bladder, ureter, or renal pelvis. It may or may not have a papillary configuration. It is graded 1 to 3 or 4 according to the degree of cellular differentiation and architectural patterns. Grade 1 transitional cell carcinoma is histologically benign but it may recur. Transitional cell carcinomas may also affect the upper respiratory tract and the ovaries.


undifferentiated gallbladder carcinoma

description: A carcinoma without evidence of differentiation arising from the gallbladder. The most common variant is the spindle and giant cell type which resembles a sarcoma.


undifferentiated ovarian carcinoma

description: An aggressive carcinoma arising from the ovary. Most patients present with advanced disease. Microscopically, it is characterized by significant cytologic atypia, increased mitotic activity, and necrosis. The prognosis is usually poor.


undifferentiated pancreatic carcinoma

description: A carcinoma with poor prognosis that arises from the pancreas. It is characterized by the presence of a significant malignant component that does not show differentiation. The malignant cells represent a mixture of large, pleomorphic cells and giant cells, or adenocarcinoma cells and spindle cells, or spindle cells.


name: undifferentiated pancreatic carcinoma with osteoclast-like giant cells

description: A rare variant of undifferentiated pancreatic carcinoma characterized by the presence of non-neoplastic osteoclast-like giant cells.


name: undifferentiated pleomorphic sarcoma, inflammatory variant

description: An undifferentiated pleomorphic sarcoma characterized by the presence of numerous inflammatory cells.


ureter carcinoma

description: A carcinoma that arises from epithelial cells of the ureter.


ureter small cell carcinoma

description: A rare carcinoma that arises from the ureter. It is characterized by the presence of small neuroendocrine cells. The prognosis is poor.


urothelial dysplasia

description: A morphologic finding indicating the presence of dysplastic changes in the transitional cell epithelium of the urinary tract.


usual ductal breast hyperplasia

description: A neoplastic ductal proliferative lesion of the breast characterized by the formation of secondary lumens and prominent intraductal proliferation of a heterogeneous cellular population that may include epithelial cells, myoepithelial cells, or metaplastic apocrine cells.


uterine carcinosarcoma

description: A usually aggressive malignant neoplasm arising from the uterine corpus and less often the cervix. It is characterized by the presence of two components: a malignant epithelial component and a sarcomatous component. In the uterine corpus the epithelial component is usually glandular whereas in the cervix is usually non-glandular. Carcinosarcoma of the cervix, although it is aggressive, it may have a better prognosis compared to the uterine corpus carcinosarcoma.


uveal melanoma

description: A melanoma derived from melanocytes of the uveal tract. It is the most common primary intraocular tumor in the United States and Western Europe. Similar to melanoma of the skin, it is rare in Africa and Asia. Diagnostic procedures include ophthalmoscopic exam, fluorescein angiography and ultrasound. Treatment includes: surgical excision of the eye, iridocyclectomy and tumor resection. Recent treatments also include radiotherapy or photo coagulation. Classification of uveal melanomas recognizes four cell types within these tumors: epithelioid, intermediate, mixed cell, and spindle cell types. The spindle cell type uveal melanomas are further sub-classified as spindle cell type A and spindle cell type B.


vaginal adenoid cystic carcinoma

description: An adenoid cystic carcinoma that arises from the vagina. Myoepithelial cells are usually not present.


vaginal carcinosarcoma

description: An aggressive mixed epithelial and mesenchymal neoplasm that arises from the vagina and is characterized by the presence of a malignant epithelial component and a malignant mesenchymal component.


vaginal melanoma

description: A primary malignant neoplasm of the vagina composed of malignant melanocytes.


vaginal squamous cell carcinoma

description: A squamous cell carcinoma arising from the vagina. Human papillomavirus infection is associated with the development of vaginal intraepithelial neoplasia and invasive squamous cell carcinoma. Signs and symptoms include painless bleeding, postcoital bleeding, and urinary tract symptoms. Morphologically it resembles squamous cell carcinomas in other anatomic sites. Radiation therapy is the preferred treatment for most cases. The prognosis is related to the stage of the disease.


vulvar lichen sclerosus

description: A chronic inflammatory disorder of unknown etiology that affects the vulva. It is characterized by the development of white elevated plaques in the vulva. Histologically there is marked subepithelial fibrosis. Clinical manifestations include pruritus, dysuria, and dyspareunia.


Warthin tumor

description: An adenoma characterized by an oncocytic, often papillary, epithelial component, dense lymphoid stroma, and cystic spaces. It occurs primarily in the parotid gland, and is the second most common benign parotid salivary gland tumor. A strong association with smoking has been reported. It typically presents as a painless swelling in the lower portion of the parotid gland.


palsy

description: A general term most often used to describe severe or complete loss of muscle strength due to motor system disease from the level of the cerebral cortex to the muscle fiber. This term may also occasionally refer to a loss of sensory function. (From Adams et al., Principles of Neurology, 6th ed, p45)


cerebral palsy

description: A group of disorders affecting the development of movement and posture, often accompanied by disturbances of sensation, perception, cognition, and behavior. It results from damage to the fetal or infant brain.


adenomatous colon polyp

description: A polypoid adenoma that arises from and protrudes into the lumen of the colon. Epithelial dysplasia is always present. According to the architectural pattern it is classified as tubular, tubulovillous, or villous.


hamartoma

description: A benign and excessive tumor-like growth of mature cells and normal tissues which grow in a disorganized pattern.


hemangioma

description: A benign vascular lesion characterized by the formation of capillary-sized or cavernous vascular channels.


acute respiratory distress syndrome

description: Progressive and life-threatening pulmonary distress in the absence of an underlying pulmonary condition, usually following major trauma or surgery. Cases of neonatal respiratory distress syndrome are not included in this definition.


acquired metabolic disease

description: An instance of metabolic disease that is acquired during the lifetime of the individual.


basal ganglia cerebrovascular disorder

description: A pathological condition caused by impaired blood flow in the basal regions of cerebral hemispheres (basal ganglia), such as infarction; hemorrhage; or ischemia in vessels of this brain region including the lateral lenticulostriate arteries. Primary clinical manifestations include involuntary movements (dyskinesias) and muscle weakness (hemiparesis).


name: congenital nonspherocytic hemolytic anemia

description: Any one of a group of congenital hemolytic anemias in which there is no abnormal hemoglobin or spherocytosis and in which there is a defect of glycolysis in the erythrocyte. Common causes include deficiencies in glucose-6-phosphate isomerase; pyruvate kinase; and glucose-6-phosphate dehydrogenase.


hereditary hemochromatosis

description: An inherited metabolic disorder characterized by iron accumulation in the tissues.


papillary carcinoma

description: A malignant epithelial neoplasm characterized by a papillary growth pattern. A papillary carcinoma may be composed of glandular cells (papillary adenocarcinoma), squamous cells (papillary squamous cell carcinoma), or transitional cells (papillary transitional cell carcinoma). Bladder carcinoma is a representative example of papillary transitional cell carcinoma.


renal tubular transport disease

description: Genetic defects in the selective or non-selective transport functions of the kidney tubules.


name: estrogen-receptor positive breast cancer

description: A subtype of breast cancer that is estrogen-receptor positive


name: estrogen-receptor negative breast cancer

description: A subtype of breast cancer that is estrogen-receptor negative


acute pancreatitis

description: An acute inflammatory process that leads to necrosis of the pancreatic parenchyma. Signs and symptoms include severe abdominal pain, nausea, vomiting, diarrhea, fever, and shock. Causes include alcohol consumption, presence of gallstones, trauma, and drugs.


childhood malignant neoplasm

description: A malignant tumor that occurs in children. Representative examples include soft tissue and bone sarcomas (e.g. osteosarcoma) and embryonal neoplasms (e.g. hepatoblastoma and rhabdoid tumor).


sporadic Creutzfeld Jacob disease

description: Sporadic Creutzfeldt-Jakob disease (sCJD) is the most common type of CJD, accounting for around 85% of cases. The precise cause of sporadic CJD is unclear, but it's been suggested that a normal brain protein changes abnormally ('misfolds') and turns into a prion. Most cases of sporadic CJD occur in adults aged between 45 and 75. On average, symptoms develop at age 60-65 years.


rectal cancer

description: A primary or metastatic malignant neoplasm that affects the rectum. Representative examples include carcinoma, lymphoma, and sarcoma.


Achenbach syndrome

description: A rare disorder which affects the volar surfaces of fingers. Clinical signs include recurrent, spontaneous or post-traumatic bruising of fingers. The clinical course of the resultant hematoma usually follows a pattern of resolution within days.


acneiform dermatitis

description: Cutaneous eruptions resembling acne, characterized by the presence of papulonodules, pustules, comedones, or cysts in the face, trunk, and extremities. Causes include infections and the use of certain medications (e.g., antibiotics and steroids).


acquired keratosis

description: Focal or diffuse thickening of the skin not inherited as a primary genetic disorder. Causes include inflammatory skin disorders, infectious disorders, lymphedema, and medications.


acrodermatitis

description: An inflammatory skin condition affecting children. It is often associated with Epstein-Barr virus infection, hepatitis B infection or cytomegalovirus infection. It is characterized by the presence of cutaneous rashes and patches on the palms and soles. The trunk is not affected.


acrodermatitis chronica atrophicans

description: An acrodermatitis characterized by a chronically progressive course, leading to widespread atrophy of the skin. It is a clinical manifestation of Lyme borreliosis.


allergic contact dermatitis

description: An inflammatory skin condition caused by an immune response to direct contact between the skin and an allergen. It consists of a delayed type of allergic reaction at the affected site with resulting red, swollen, and blistered skin that may itch or leak.


allergic urticaria

description: A urticaria with a basis in a pathological type I hypersensitivity reaction.


anhidrosis

description: Lack of sweating or the ability to sweat when provoked by the appropriate stimulus.


bacterial exanthem

description: A bacteria-induced exanthem


cholesteatoma

description: A pathologic process characterized by the proliferation of keratinizing squamous epithelium resulting in the accumulation of keratin and cells in the middle ear and/or mastoid. It may be congenital or acquired. If left untreated, it may increase in size and destroy adjacent structures.


cholesteatoma of attic

description: A cholesteatoma in the attic


cholesteatoma of external ear

description: A cholesteatoma (disease) that involves the external ear.


cholesteatoma of middle ear

description: A non-neoplastic lesion characterized by the proliferation of keratinizing squamous epithelium in the middle ear that results in the accumulation of keratin and cells. It is usually caused by repeated infections. If left untreated, it may increase in size and destroy the adjacent delicate bones of the middle ear.


cholinergic urticaria

description: A type of physical urticarias (or hives) that appears when a person is sweating.


congenital generalized lipodystrophy

description: An extremely rare autosomal recessive condition, characterized by an extreme scarcity of fat in the subcutaneous tissues.


conjunctival pigmentation

description: Pigmented lesions that arise from the conjunctiva include nevus, complexion-associated melanosis (CAM), primary acquired melanosis (PAM), and malignant melanoma.1,2All of these lesions arise from melanocytes. However, a number of other lesions have a similar appearance but a different source, such as pigment deposits from silver and iron.


diffuse lipomatosis

description: A neoplastic process characterized by a diffuse poorly circumscribed overgrowth of adipose tissue. It has been associated with several genetic disorders and different clinical conditions such as liver disease, excessive alcohol intake, adrenocortical steroid therapy, and antiretroviral therapy.


dyshidrosis

description: A recurrent eczematous reaction characterized by the development of vesicular eruptions on the palms and soles, particularly along the sides and between the digits. It is accompanied by pruritus, a burning sensation, and hyperhidrosis. The disease is self-limiting, lasting only a few weeks. (Dorland, 27th ed)


epidermolysis bullosa

description: Epidermolysis bullosa (EB) is a group of genetic skin diseases that cause the skin to blister very easily. Blisters form in response to minor injuries or friction, such as rubbing or scratching. There are four main types of epidermolysis bullosa: dystrophic epidermolysis bullosa Epidermolysis bullosa simplex Junctional epidermolysis bullosa Kindler Syndrome Identifying the exact type can be hard because there are many subtypes of EB. Within each type or subtype, a person may be mildly or severely affected. The disease can range from being a minor inconvenience to completely disabling, and fatal in some cases. Most types of EB are inherited. The inheritance pattern may be autosomal dominant or autosomal recessive. Management involves protecting the skin, reducing friction against the skin, and keeping the skin cool.


epidermolysis bullosa dystrophica

description: A genetic skin disorder caused by mutations in the type VII collagen gene (COL7A1). It is characterized by the formation of blisters and scarring in the skin and mucous membranes.


erythema infectiosum

description: A self-limited viral infectious disorder caused by the human parvovirus B19. It affects predominantly children and is characterized by the development of a bright red skin eruption in the cheeks. It is followed by a maculopapular skin eruption in the extremities which eventually fades into a lacey pattern.


erythema multiforme

description: Erythema multiforme (EM) refers to a group ofhypersensitivity disorders characterized by symmetric red, patchy lesions, primarily on the arms and legs. The cause is unknown, but EM frequently occurs in association with herpes simplex virus, suggesting an immunologic process initiated by the virus. In half of the cases, the triggering agents appear to be medications, including anticonvulsants, sulfonamides, nonsteroidal anti-inflammatory drugs, and other antibiotics. In addition, some cases appear to be associated with infectious organisms such as Mycoplasma pneumoniae and many viral agents. Erythema multiforme is the mildest of three skin disorders that are often discussed in relation to each other. It is generally the mildest of the three. More severe is Stevens-Johnson syndrome. The most severe of the three is toxic epidermal necrolysis (TEN).


erythematosquamous dermatosis

description: A skin condition that primarily affects the scalp and face and presents as scaly inflammation. Examples include itchy, dry skin and dandruff.


exanthem

description: Any change in the skin which affects its appearance or texture. A rash may be localized to one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, dry, cracked or blistered, swell and may be painful.


facial dermatosis

description: Facial Dermatosis, also known as facial dermatoses, is related tolipogranulomatosis. An important gene associated with Facial Dermatosis isCCNE1(cyclin E1). The drugsbetamethasoneandbetamethasone acetatehave been mentioned in the context of this disorder.


fibroepithelial polyp of the anus

description: A non-neoplastic polypoid lesion that arises from the anal canal or perianal skin. It is composed of dense fibrous stroma and it is covered by squamous epithelium.


fibroepithelial polyp of urethra

description: A benign polypoid lesion of mesodermal origin that arises from the urethra.


alopecia mucinosa

description: A rare dermatologic disorder characterized by the accumulation of mucinous material in the hair follicles. In some cases it is associated with lymphoproliferative disorders, most often mycosis fungoides and Hodgkin lymphoma.


folliculitis

description: Inflammation of the hair follicles. Causes include excessive perspiration, skin infections, and skin wounds.


Fox-Fordyce disease

description: A chronic skin disease most common in women aged 13-35 years.It is characterized by the development of intense itching in the underarm area, the pubic area, and around the nipple of the breast as a result of perspiration which becomes trapped in the sweat gland and surrounding areas. The cause is unknown, but heat, humidity, and stress may play a role. Treatment may include the use of retinoids, antibiotics, and immunosuppressants.


granuloma annulare

description: Granuloma annulare is a long-term (chronic) skin disease consisting of a rash with reddish bumps arranged in a circle or ring. The most commonly affected areas are the forearms, hands and feet. The lesions associated with granuloma annulare usually resolve without treatment. Strong steroids (applied as a cream or injection) are sometimes used to clear the rash more quickly. Most symptoms will disappear within 2 years (even without treatment), but recurrence is common. The underlying cause of granuloma annulare is unknown.


granulomatous dermatitis

description: An inflammatory reaction of the skin to various organic and inorganic antigens. It is characterized by tumor-like masses or nodules of granulomatous tissue comprised of activated histiocytes, epitheliod cells, and multinucleated giant cells.


hand dermatosis

description: Skin conditions characterized by dense infiltration of inflammatory cells (neutrophils) in the affected tissue. They arise in reaction to some underlying systemic illness. A neutrophilic dermatosis may be seen in isolation or more than one type may occur in the same individual.


hemangioma of subcutaneous tissue

description: A hemangioma arising from the subcutaneous soft tissues.


pemphigoid gestationis

description: A rare pregnancy-associated autoimmune skin disease that is characterized by an itchy rash that develops into blisters. It is most common during the second and third trimesters of pregnancy. It was previously known as herpes gestationis although it has no association with the herpes virus whatsoever.


hidradenitis suppurativa

description: A chronic suppurative and cicatricial disease of the apocrine glands occurring chiefly in the axillae in women and in the groin and anal regions in men. It is characterized by poral occlusion with secondary bacterial infection, evolving into abscesses which eventually rupture. As the disease becomes chronic, ulcers appear, sinus tracts enlarge, fistulas develop, and fibrosis and scarring become evident.


eyelid hypopigmentation

description: Under-production of pigment in the eyelid.


inverted follicular keratosis

description: Seborrheic keratosis that arises from follicular structures in the skin. It presents as a solitary nodule in the skin and is characterized by the presence of prominent squamous eddies.


irritant dermatitis

description: An inflammatory skin condition caused by direct contact between the skin and an irritating substance. It is typically manifested by erythema, mild edema, and scaling at the affected site.


juvenile dermatitis herpetiformis

description: Dermatitis herpetiformis in children


keratosis

description: A skin disorder consisting of hypertrophy of the stratum corneum of the skin.


kernicterus due to isoimmunization

description: Encephalopathy in infants due to high levels of unconjugated bilirubin that are a result of Rh incompatibility between the mother and the fetus.


leg dermatosis

description: A nonspecific term used to denote any cutaneous lesion or group of lesions, or eruptions of any type on the leg. (From Stedman, 25th ed)


lichen disease

description: A long-term skin condition that mainly affects the skin of the genitals. It usually causes itching and white patches to appear on the affected skin.