Cystic trophoblastic tumour of the testis: Case report.

Cystic trophoblastic tumor (CTT) is a rare non-aggressive germinative neoplasm from the group of non-choriocarcinomatous trophoblastic tumors, which is presented by cystic spaces lined with mononuclear degenerative-looking trophoblastic cells. CTT has been most often described as a residual disease in dissected retroperitoneal lymph nodes of patients with metastatic germ cell testicular tumours after chemotherapy. There were published only sporadic cases of primary testicular mixed germ cell tumour with CTT component. Hereby, the authors present a case of a 22-year-old man with a mixed germ cell tumour composed of postpubertal teratoma, embryonal carcinoma and CTT. Immunohistochemically, the CTT tumour cells were positive for cytokeratins (AE1/AE3, CK8/18), GATA3, p63 and focally also for beta-hCG and alpha-inhibin. CTT may be presented as a rare component of primary testicular mixed germ cell tumour and it represents very likely an evolutionary intermediate stage of transition from choriocarcinoma into teratoma during the process of regression.