Malignant interstitial cell tumor of the testis.

A case of malignant interstitial cell tumor of the testis is reported and the literature is reviewed. Malignant interstitial cell tumors occur exclusively in adults. Gynecomastia was noted in 12% of the cases. Elevated plasma levels or increased urinary excretion of estrogen, 17-ketosteroid, or testosterone were demonstrated in 64% of the patients. Vessel invasion, which occurred in 74% of the patients, appears to be the only reliable histologic feature for predicting malignant behavior. There is no proved sensitivity to radiation or chemotherapeutic regimens in patients with disseminated tumor. Once the diagnosis of malignancy is histologically established, inguinal and retroperitoneal lymph node dissections, even in the absence of clinical evidence of metastasis, may be beneficial in providing early staging of the tumor and, perhaps, in preventing subsequent lymphatic spread.