Primary pure teratoma of the testis.

PURPOSE: Despite its histologically benign appearance, primary pure teratoma of the testis is believed to have metastatic potential and behave similarly to other nonseminomatous germ cell tumors. We present our experience with the natural history and management of pure teratoma.

MATERIALS AND METHODS: We reviewed the histological findings and clinical history of 15 patients with primary pure teratoma who were treated during a 15-year period, accounting for 4.2% of all nonseminomatous germ cell tumors treated during the same period. Fourteen patients were available for followup and are included in this report.

RESULTS: In 8 patients the tumor was composed entirely of mature teratoma and in 6 immature elements were also present, although this finding was not associated with an increased frequency of metastatic disease. Carcinoma in situ was found adjacent to the tumor in 12 cases. Of 10 patients with stage I disease at presentation who were entered on a surveillance program only 2 have had relapse. The remaining 4 patients had metastatic disease at presentation and, thus, metastatic disease occurred in a total of 6 of the 14 patients (43%) with a median followup of 46 months (range 5 to 197). Metastatic disease was confined to the retroperitoneum in all 6 patients and only 2 patients had elevated serum marker levels. Five patients were treated with primary chemotherapy followed by resection of a residual mass and in all cases teratoma was identified in the resected mass. One patient underwent surgical excision of a retroperitoneal mass, which contained teratoma and yolk sac tumor, followed by chemotherapy. All patients are alive without evidence of progressive disease.

CONCLUSIONS: In patients with primary pure teratoma of the testis metastatic disease may develop and the metastases may contain other subtypes of nonseminomatous germ cell tumors in addition to teratoma. There is probably a reduced frequency of relapse, which should be considered when advising patients with stage I disease, but otherwise management should be the same as for other testicular nonseminomatous germ cell tumors and the prognosis should be excellent.