Abstract
On of 7 patients with pure dysgerminoma had slightly elevated serum human chorionic gonadotropin (HCG) and α-fetoprotein (AFP) levels as determined by radio-immunoassay before operation. The values returned to the normal range after the removal of the tumor. The cells that produced the HCG or AFP were identified by immunohistochemical staining of the tumor tissues. HCG proved positive both in the multinucleated giant cells with eosinophilic cytoplasm and in the spindle-shaped cells with a hyperchromatic nucleus. AFP was positively stained in the round cells. These results suggest that HCG and AFP are produced by the cells which constitute pure dysgerminoma.