IMMUNOHISTOCHEMICAL COMPARISON BETWEEN ANAPLASTIC SEMINOMA AND TYPICAL SEMINOMA

In order to study the possible biological differences between anaplast ic and typical seminoma, the following factors were studied in 11 case s of anaplastic seminoma and 15 cases of typical seminoma: mitotic act ivity, proliferating cell nuclear antigen (PCNA) expression, immunohis tochemical analyses for cytokeratin, vimentin, placental alkaline phos phatase (FLAP), beta-human chorionic gonadotropin (beta-hCG), alpha-fe toprotein (AFP) and c-myc oncoprotein. Anaplastic seminoma was classif ied according to Mostofi's criteria, which is primarily based on the m itotic activity of the tumor. Mitotic activity was evaluated by both m itotic count and rate. Statistically significant correlations were obs erved between mitotic count and mitotic rate (R = 0.891), and between the mitotic count and PCNA labeling index (R = 0.792), in both typical and anaplastic seminomas. Immunostaining patterns for cytokeratin, vi mentin, PLAP, beta-hCG, AFP and c-myc oncoprotein were not significant ly different between typical and anaplastic seminoma. The present data indicated that no apparent clinicopathologic and immunohistochemical parameters discerning anaplastic seminoma from typical seminoma were p resent, when identifying anaplastic seminoma on the basis of high mito tic count. Anaplastic seminoma may therefore simply represent seminoma with high proliferative activity.