Cystic trophoblastic tumor - The effect of chemotherapy in metastatic testicular germ cell tumor to retroperitoneal lymph nodes.

Cystic trophoblastic tumor is an uncommon lesion which is occasionally seen after chemotherapy in metastatic retroperitoneal lymph nodes in patients with testicular germ cell tumor. The tumor cell clusters show cystic change lined by single to multiple layers of cells with abundant dense eosinophilic vacuolated cytoplasm, large pleomorphic vesicular nuclei with smudged chromatin, and prominent nucleoli. It is important to identify this lesion as its prognosis is similar to a teratoma and does not require any additional chemotherapy.