Pure Choriocarcinoma of Testis with Tumor-Infiltrating Lymphocytes and Granulomas

Pure choriocarcinoma is very rare in the testes, and host immune responses including tumor infiltrating lymphocytes are unusual in choriocarcinoma. This study reports a case of pure testicular choriocarcinoma with extensive lymphocytic infiltrate and granulomatous inflammation. Scrotal ultrasonography revealed a heterogeneous, hyperechoic intratesticular mass. β-human chorionic gonadotropin levels were elevated in a radioimmunoassay. The hemorrhagic and necrotic solid mass was composed of two cell populations - mononuclear pleomorphic cells and intimately admixed multinucleated smudged cells. The tumor cells were positive for cytokeratin 7, epidermal growth factor receptors, human placental lactogen and p57. Many inflammatory cells were present within the tumor. The majority of infiltrating cells were CD8-positive cytotoxic cells, which also expressed granzyme-B and TIA-1. The tumor cells were positive for FasL, but negative for Fas. Therefore, this case seemed to escape the host defense response to the tumor due to the loss of Fas, although the cellular host immune response was still active.