Spermatocytic seminoma as compared to classical seminoma: An immunohistochemical and DNA flow cytometric study

Based on immunohistochemistry (IHC) and DNA ploidy, different paths of carc inogenesis have been suggested for spermatocytic seminoma (SS) and classica l seminoma (CS). The present study extends current knowledge on the above p arameters. Method. Seventeen SSs and twenty-two CSs were assessed by IHC fo r placental-like alkaline phosphatase (PLAP), c-kit, cytokeratin and adhesi on carbohydrate molecyles. All SSs and 11 CSs were also analysed for DNA pl oidy. Results. All CSs, but none of the SSs, were positive for FLAP. C-kit positivity was found in 7 of 17 SSs and in all CSs. The other IHC parameter s were similarly distributed among the evaluated SSs and CSs. Fourteen SSs were diploid or polyploid, and three were aneuploid. All CSs were aneuploid . Conclusion. The new observation of c-kit positivity in about 40% of SSs s uggests that at least some of the SSs originate from primordial cells. The predominantly diploid or polyploid DNA pattern indicates that SSs follow a pathogenetic pathway which is most probably different from that of CSs.