Malignant germ cell tumors of the ovary and testis. An immunohistologic study of 69 cases.

An immunohistologic study of 21 patients with germ cell tumors of the testis with m easured serum levels o f hum an chorionic gonadotropin (HCG) and alpha fetoprotein (AFP) was undertaken to correlate the various types of neoplasms with the presence of these tum or markers in the tissue and serum. The same immunoperoxidase technique was applied to 48 patients with m alignant germ cell tumors of the ovary in whom serum was not available. In the testicular tumor group, AFP was dem onstrated in m ononuclear embryonal cells w ithin embryonal carcinoma and endoderm al sinus tumor. HCG was identified w ithin syncytiotrophoblastic giant cells frequently in association with embryonal carcinoma, and rarely with endoderm al sinus tum or and seminoma, as w ell as in the syncytiotrophoblastic com ponent of choriocarcinoma. E ighteen of the 21 patients (86 percent) had elevated tumor markers in their serum; serum HCG alone was elevated in 5 (24 percent), AFP alone in 5 (24 percent) and both were elevated in 8 (38 percent). There was tissue localization of HCG in 12 of 13 patients (92 percent) w ith elevated serum HCG while AFP was identified in the tumor in eight of the 13 patients (53 percent) with elevated serum AFP levels. In the ovarian tumor group, all 15 endoderm al sinus tumors examined were positive for AFP and negative for HCG. Seven of 10 embryonal car­ cinomas were positive for AFP and all 10 were positive for HCG. The two cases of choriocarcinoma were both positive for HCG and negative for AFP. In contrast, the 11 dysgerminomas and 10 teratomas were negative for both AFP and HCG. The results parallel those for malignant germ cell tumors of the testis, affording additional evidence of the analogous nature of germ cell tumors of the gonads. Based on these findings a tentative imm unohisto­ logic classification of germ cell tumors utilizing AFP and HCG is proposed. Thus, embryonal carcinoma is frequently associated with both AFP and HCG, endoderm al sinus tum or w ith AFP and choriocarcinoma with HCG, whereas pure seminoma, dysgerminoma and teratoma are unlikely to be associated w ith either marker. * Present Address: Georgetown University, School o f M edicine, Department of Pathology, 3800 Reservoir Road, Washington, DC 20007.