Anaplastic variant of spermatocytic seminoma.

Four examples of spermatocytic seminoma with a predominant anaplastic component occurred in men 33 to 43 years of age, without histories of cyptorchidism. The seminomas presented with painless testicular masses recognized 3 to 18 months before orchiectomy. Preoperative serum measurements of human chorionic gonadotropin and alpha-fetoprotein were negative. All tumors contained areas (10% to 30% of the tumor) in which the three cell types characteristic of conventional spermatocytic seminoma could be identified under light microscopy. The predominant anaplastic component also contained the three cell types, but the nuclei had prominent nucleoli with granular and filamentous chromatin. In addition, sheets of cells with vesicular nuclei and prominent nucleoli superficially resembling embryonal carcinoma were found. There were numerous large mononuclear and multinucleated giant cells with bizarre nuclei and prominent nucleoli, but no sarcomatous elements. Many normal and abnormal mitotic figures were present. Tunical and vascular invasion and extensive necrosis were constant features. Immunohistochemistry documented p53 protein overexpression in two tumors, but neoplastic cells were negative with immunostains for placenta-like alkaline phosphatase, leukocyte common antigen, neuron-specific enolase, alpha-fetoprotein, human chorionic gonadotropin, vimentin, and cytokeratins. Ultrastructural examination of the anaplastic component showed large rope-like nucleoli, but the cytoplasmic features were similar to those of conventional spermatocytic seminoma. Despite the presence of a major anaplastic component, no patient has developed metastasis. Larger series and longer follow-up are needed to understand the natural history of these neoplasms.