Sertoli-Leydig cell tumor of the ovary with alpha-fetoprotein production.

A case of poorly differentiated Sertoli-Leydig cell tumor with elevated serum alpha-fetoprotein (AFP) levels occurred in a 17-year-old girl. No germ cell component and no heterologous elements were identified, but a retiform pattern was present. Immunohistochemical studies demonstrated immunoreactivity for AFP and testosterone in Leydig's cells only. Secretion of AFP by Sertoli-Leydig cell tumors has rarely been mentioned previously, and its mechanism is difficult to explain. Non-germ cell tumors must be considered in the differential diagnosis of ovarian tumors with elevated serum AFP levels.