label: Borderline Paratesticular Serous Tumor
label_lc: borderline paratesticular serous tumor
description: A rare, non-invasive, serous cystic tumor that arises from the paratesticular structures. It is characterized by the presence of irregular papillary formations with irregular branching. The papillae are lined by atypical columnar epithelial cells with eosinophilic cytoplasm. Mitoses are rare. Metastases have not been reported.