Lectin histochemistry of human testicular germ cell tumors

The lectin binding pattern (WGA, UEA-I, PNA, PSA, Con A, RCA and LCA) of 28 human testicular germ cell tumors (pure or combination tumors) was investigated. Lectin binding sites could be demonstrated in all germ cell tumor types. In classic and spermatocytic seminomas as well as seminomas with high mitotic index an equal distribution of lectin binding sites was observed. In embryonal carcinomas the lectin binding of UEA-I, PNA, WGA, LCA and RCA correlated to histological differentiation. A polarized staining of WGA, PNA, RCA and UEA-I, typical for embryonal carcinomas, yolk sac tumors and teratomas, was never seen in seminomatous tumors and may be of importance in differential diagnosis. By means of Con A decoration it was possible to distinguish cytotrophoblastic and syncytiotrophoblastic differentiation. Aspects of lectin histochemistry in tumor biology in general and in differential diagnosis of germ cell tumors in particular are discussed.