Cystic
trophoblastic tumor (CTT) is an uncommon lesion that is usually seen after
chemotherapy in patients with testicular
germ cell tumors. Its clinical significance has not been well studied. We identified 17 patients with CTT in retroperitoneal
lymph node dissections (RPLNDs) after
cisplatin-based
chemotherapy for testicular
germ cell tumors. None had other forms of persistent
germ cell tumor except for
teratoma, and no patient received additional
chemotherapy after RPLND. At the time of RPLND, 7 patients were known to have had normal serum levels of beta-subunit of
human chorionic gonadotropin (beta-hCG), whereas 5 had relatively mild elevations (1.6-165 mIU/mL, median, 8.0 mIU/mL). The CTTs consisted of 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. On follow-up of 15 patients, 11 were disease free (mean, 80 months). Three recurred with serum
alpha-fetoprotein elevations at 25, 31, and 107 months, respectively, and one with beta-hCG elevation at 2 months. The latter patient, however, also had unresected mediastinal
tumor postchemotherapy. We conclude that the finding of CTT in postchemotherapy resections does not warrant additional
chemotherapy. Its clinical significance appears similar to that of residual
teratoma.