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

Based on immunohistochemistry (IHC) and DNA ploidy, different paths of carcinogenesis have been suggested for spermatocytic seminoma (SS) and classical seminoma (CS). The present study extends current knowledge on the above parameters. Method. Seventeen SSs and twenty-two CSs were assessed by IHC for placental-like alkaline phosphatase (PLAP), c-kit, cytokeratin and adhesion carbohydrate molecyles. All SSs and 11 CSs were also analysed for DNA ploidy. 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 parameters 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 suggests 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.