label: T Lymphoblastic Leukemia/Lymphoma
label_lc: t lymphoblastic leukemia/lymphoma
description: A neoplasm of lymphoblasts committed to the T-cell lineage, typically composed of small to medium-sized blast cells.  When the neoplasm involves predominantly the bone marrow and the peripheral blood, it is called T acute lymphoblastic leukemia.  When it involves nodal or extranodal sites it is called T lymphoblastic lymphoma. (WHO, 2001)