Primary retroperitoneal seminoma. Report of a case and review of the literature.

A large retroperitoneal seminoma in a 42-year-old man is described, which appears to have arisen as a primary tumor at that site. The mechanism for the development of extragonadal germ cell tumors is discussed, and the criteria for their distinction from metastatic occult or regressed testicular neoplasms are re-emphasized. Awareness by clinicians of this entity may save individuals with this neoplasm from unnecessary orchiectomy.