[HCG-positive cells in seminoma of the testis].

In a retrospective study of 38 patients with pure seminoma, serum and urine levels of human chorionic gonadotropin (HCG) were measured and the cellular origin of HCG-like substance was searched using the technique of indirect immunoperoxidase on step sections of the tumors. Eight of the patients had elevated HCG in serum or urine, and 5 had HCG-positive cells in the sections of tumor specimens. With this technique, two types of HCG-positive cells were identified, syncytiotrophoblastic giant cells (STGC) and mononuclear cells otherwise indistinguishable from seminoma cells. Patients in the present series responded well to conventional radiation therapy or cytotoxic chemotherapy and had a favorable outcome regardless of the presence of STGC or slightly elevated HCG levels.