Therapy-resistant metastasizing anaplastic spermatocytic seminoma: a cytogenetic hybrid: a case report

Anaplastic spermatocytic seminoma is a rare variant of the conventional spermatocytic seminoma, with only 6 cases reported up to now. The anaplastic variant contains only the medium-sized cell type, hallmarked by large-sized nucleoli, whereas the small lymphocyte-like and giant cells typical of the conventional spermatocytic seminoma are lacking.

We report herein an unusual case of a 40-year-old man with an anaplastic spermatocytic seminoma which metastasized first to the retroperitoneal lymph nodes and, something never before reported, subsequently to the lung and other organs. The immunophenotype with c-kit and SALL4 positive and PLAP, as well OCT 3/4 negative tumor cells were identical to those of conventional spermatocytic seminoma. Cytogenetically the tumor cells showed a gain of chromosome 9, typical for spermatocytic seminoma, but simultaneously also the short arm 12p were overexpressed--an overexpression crucial to the aggressive behavior of seminomas and other nonseminomatous tumors but never before encountered in spermatocytic seminoma.

The current opinion is that seminoma and nonseminomatous germ cell tumors develop from a common primitive progenitor cell, whereas spermatocytic seminomas develop from differentiated spermatogonia. The herein presented cytogenetic hybrid tumor shows that a crossover between the two different histogenetic "tracks" is possible.