[The synchronous appearance of multiple testicular epidermoid cysts and of a malignant mixed germinal tumor in the contralateral testis].

We describe the simultaneous appearance of multiple epidermoid cysts in the right and an adult teratoma containing embryonal carcinoma and choriocarcinoma in the left testis. No similar case has previously been described. Epidermoid cysts of the testis are rare, accounting for about 1% of all testicular tumors. Epidermoid cysts are now regarded as monoepidermally developed teratomas of germ cell origin. Testicular teratomas in adults, however, are always malignant. Because epidermoid cysts are rare tumors, primary therapy often consists in ablation of the testis. In the case described, excision of the epidermoid cyst protected the patient from complete castration. This case demonstrates the simultaneous appearance of a malignant and a benign testicular germ cell tumor.