[Importance of determination of various histologic components in testicular germ cell tumors]

Testicular germ cell tumors represent about 95% of all testicular tumors. They are often composed of many different components. Seminoma usually has a favorable course but the prognosis of mixed germ cell tumors is depending on the type and proportion of different histologic components. The aim of this study was to determine the proportion and histologic type of various components of testicular germ cell tumors diagnosed in the period 1992-2000. In this period there were 131 testicular germ cell tumors with 72 (55.0%) nonseminomatous and 59 (45.0%) seminomatous tumors. Of all nonseminomatous tumors, 4 were composed of one component only, and 68 contained different components. Nonseminomatous tumors contained most commonly embryonal carcinoma (91.7%), teratoma (70.8%) and yolk sac tumor (33.3%) components. The most frequent combination of mixed germ cell tumors was composed of teratoma and embryonal carcinoma in 28 (41.2%) cases. Seminoma was found in 59 cases as pure seminoma and in 19 (26.4%) additional cases represented a component of testicular mixed germ cell tumor. Analysis of deeper sections by means of HE stained slides and immunohistochemistry (cytokeratin, CD30, alpha-fetoprotein, beta-HCG, PLAP and hPL) revealed 20 cases with components that were not described in original biopsy findings. We may conclude that the analysis of many sections using immunohistochemistry is necessary to identify all tumor components.