Miscellaneous rare paratesticular tumors

A few uncommon but distinctive tumors may preferentially involve the parate stis. The 3 unusual tumors that represent the focus of this discussion are the ovarian-type epithelial tumors (OTET), the desmoplastic small round cel l tumor (DSRCT), and the melanotic neuroectodermal tumor of infancy (MNTI). The OTETs are testicular homologues of their more common namesake counterp arts that arise in the ovary, Most frequent of these are serous tumors of b orderline malignancy, with fewer cases of serous carcinomas or other forms of mullerian differentiation. DSRCT is an increasingly recognized, aggressi ve, "small blue cell" neoplasm with distinctive clinical and pathologic fea tures. These polyphenotypic tumors characteristically, but not invariably, arise in intimate association with the serosal membrane of the peritoneal c avity and harbor a signature translocation-t(11;22)(p13,q12). In the parate stis they often involve the surface of the epididymis, The MNTI is an enigm atic, histologically distinctive, low-grade neoplasm occasionally encounter ed in the epididymis. Recognition of its features is essential to avoid mis diagnosis as a more aggressive "small blue cell" neoplasm and consequent th erapeutic mismanagement, Primary hematopoietic tumors of the paratesticular structures are rare. There appears to be a tendency for young men to have low-grade lymphomas with an indolent course and older patients to develop h igher-grade tumors. Plasmacytoma and granulocytic sarcoma of the paratestis are even more rare and are often susceptible to misinterpretation. Finally , metastatic tumors and a variety of other very rare neoplasms are discusse d. Copyright (C) 2000 by W,S. Saunders Company.