Testicular germ cell tumor seven years after a retroperitoneal germ cell tumor.

A 44-year-old male was diagnosed in August 1980 as having a retroperitoneal germ cell tumor (classic seminoma with anaplastic areas). After treatment with cisplatin-based chemotherapy, he reached complete clinical and pathological remission. Eighty-eight months later, in December 1987, he was diagnosed as having a testicular mixed germ cell tumor (embryonal carcinoma with anaplastic seminoma areas) after right orchiectomy. The potential mechanisms by which the latter tumor could have developed are discussed.