Metastatic pure choriocarcinoma of the testis in an elderly man.

The case described of pure choriocarcinoma of the testis is rare because of the histological type and patient age at presentation. A 63-year-old man had a 160 gm. tumor, with a necrotic, hemorrhagic appearance and sparse bright areas that consisted exclusively of syncytial and cytotrophoblastic cells. Immunocytochemical analysis revealed strong staining for human chorionic gonadotropin in the syncytiotrophoblastic cells. The specimen was moderately positive for keratin and negative for alpha-fetoprotein.