Primary retroperitoneal seminoma.

In a retrospective review (1950-1975) of the Mayo Clinic experience with seminomas (483 cases), twelve patients (2.5%) were found to have a retroperitoneal seminoma without evidence of testicular involvement. The mean age was 47 years (range, 31-67). Eleven patients were treated by radiation alone, with doses ranging from less than 2,000-5,800 rads. Seven patients are alive with a median follow-up of six years. The median survival of the five that died is ten months. Good prognostic factors are typical histopathology and an encapsulated tumor. Poor prognostic factors are atypical histopathology, a nonencapsulated tumor, a symptomatic abdominal mass and a nonfunctioning kidney at the time of diagnosis. Although the review includes few patients, it seems reasonable to suggest irradiation of the tumor bed and para-aortic lymph nodes to a minimum dose of 2,000 rads. Prophylactic treatment of the mediastinum and supraclavicular lymph nodes should be considered if one or more of the poor prognostic factors are present.