Cystic trophoblastic tumor (CTT) is an uncommon lesion that is usually seen after chemotherapy in patients with testicular germ cell tumors.
Synopsis
circumscribed, small cysts, usually multifocal, lined by mostly mononucleated trophoblast cells with abundant eosinophilic cytoplasm, often with smudged nuclei and showing only infrequent mitotic figures.
Although the epithelial lining was often stratified to several layers in thickness or formed intracystic papillary tufts, solid proliferations of trophoblast cells within the stroma were absent, as were clearly biphasic admixtures of mononucleated and multinucleated trophoblast cells.
The cysts were either empty or contained fibrinoid material and were set in a hypocellular, fibrous stroma with adjacent teratoma. Stains for hCG highlighted rare cells.
References
Ulbright TM, Henley JD, Cummings OW, Foster RS, Cheng L. Cystic trophoblastic tumor: a nonaggressive lesion in postchemotherapy resections of patients with testicular germ cell tumors. Am J Surg Pathol. 2004 Sep;28(9):1212-6. PMID: 15316321