Adenocarcinoma of the rete testis. Case report, ultrastructural observations, and clinicopathologic correlates.

Adenocarcinoma of the rete testis is a rare tumor that tends to occur in men over the age of 60 and is usually associated with a poor prognosis. We report such a tumor occurring in a 63-year-old male 2 years after he underwent a scrotal exploration in the management of a hydrocele, varicocele, and inguinal hernia. The postorchidectomy course was characterized by slowly advancing, painful scrotal and perineal skin recurrences, lymph node metastases, and the absence of response to Adriamycin and electron-beam therapy. We are confident that the lesion is a carcinoma of the rete testis because: 1) the tumor is situated mainly in the testicular mediastinum, 2) primary germinal and nongerminal testicular tumors and spread from distant sources have been excluded, 3) a transition from normal rete testis to atypical and neoplastic rete epithelium is demonstrable, and 4) the transmission electron-microscopic findings support our conclusion. The distinction between carcinoma of the rete testis and malignant mesothelioma may be difficult and requires consideration of the gross, light-microscopic, and ultrastructural tumor characteristics in optimally fixed tissue.