[An immunohistochemical study on neuron specific enolase in testicular germ cell tumors]

Testicular germ cell tumors obtained from 44 patients were immunohistochemically studied using anti-neuron specific enolase (NSE) antibody. The level of NSE in the serum was also measured in 9 patients before and after extirpation of the tumor. As for tumor cells of seminoma, 19 of 20 pure seminomas and all 9 of mixed type were positive for NSE. On the contrary, a spermatocytic seminoma was NSE-negative. As for embryonal carcinomas, some tumor cells were NSE-positive in 13 of 15 of mixed type. In yolk sac tumor, a few tumor cells were also NSE-positive in 8 of 21 of both pure and mixed types. Some NSE-positive cells were found in teratomatous components of 10 of 14 mature and immature teratomas of both pure and mixed types. These were in neural cells, chondrocytes, and glandular epithelial cells. Spermatogonia in 5 normal testes were NSE-positive. NSE level in the serum was elevated before extirpation and decreased after extirpation in 4 of 5 cases of seminoma of pure type and in 1 of 2 of mixed type which included seminomatous elements. All of these cases were either in the advanced stage or had a rather large primary tumors. Immunohistochemical study of testicular germ cell tumors using anti-NSE antibody may facilitate histological diagnosis, and serum NSE level may be useful for monitoring the clinical course as well as for clinical diagnosis of seminoma.