RESUMEN
<p><b>OBJECTIVE</b>To study the clinicopathologic features and biological behavior of spermatocytic seminoma.</p><p><b>METHODS</b>A retrospective analysis of patients diagnosed as seminoma, spermatocytic seminoma between January 2003 and May 2011, was performed. Clinical data, HE stained section and immunohistochemical staining (SP method) were reviewed with follow-up.</p><p><b>RESULTS</b>Sixty-six cases of seminoma and 5 cases of spermatocytic seminoma were identified. The average age at the diagnosis of 5 cases of spermatocytic seminoma was 53 years, and no patient had a history of crytorchidism or germ cell tumor. All five patients had stage pT1 tumor. Immunohistochemical studies showed that spermatocytic seminoma was negative for CK, vimentin, OCT3/4, PLAP, and LCA, and PAS staining was also negative. All five patients were well after operation. In contrast, the average age at diagnosis of the 66 cases of seminoma was 37 years, in which 12% had a history of crytorchidism and 11% were in stage pT2 or the above. Immunohistochemical studies showed that seminoma was positive for OCT3/4, PLAP, and CD117. During the follow-up, 2 patients developed metastasis and 3 patients died of the disease.</p><p><b>CONCLUSIONS</b>Spermatocytic seminoma is rare and appears to follow a benign clinical course Due to its favourable prognosis, further treatment is not necessary after orchidectomy. Accurate pathologic diagnosis is critical for patient management and for avoiding over-treatment.</p>