Non-choriocarcinomatous trophoblastic tumors of testis in postchemotherapy retroperitoneal lymph node dissections

Non-choriocarcinomatous trophoblastic tumors (NCTTs) are seldomly diagnosed in male genital tract. As they have been recently described among the testicular germ cell tumor (TGCT) variants, pathologists' familiarity with their morphology is limited. We searched our electronic hospital records covering the years 2000-2017 for post-chemotherapy retroperitoneal TGCT metastectomies. Slides of all cases with viable tumor were retrieved from the archives and reviewed. Cases suspected of N-CTT morphologies were subjected to immunohistochemistry. Twelve NCTTs were identified, 9 of which were unseen or misdiagnosed by the original pathologists: Cystic trophoblastic tumor (CTT) (n = 5), placental site trophoblastic tumor (n = 2), epithelioid trophoblastic tumor (ETT) (n = 4), and coinciding PSTT + ETT (n = 1). Eight of these were associated with mature teratoma components, and one case (ETT) contained embryonal carcinoma and yolk sac tumor in addition to teratoma. Ten patients were clinically N1 at the time of primary tumor detection and orchiectomy. One patient had burned-out primary testicular tumor. Six patients were clinical M1a at presentation, while one male was cM1b. Six patients had mildly elevated β-HCG (≤ 410 mIU/ml) just prior to retroperitoneal lymph node dissections (RPLND), while the others had normal β-HCG levels. All patients had follow-ups ranging from 8 to 118 months (mean 42.3 months). Three patients died of disease-related and two of unrelated causes. In conclusion, because NCTTs are rare and newly described tumor types, their diagnosis is difficult and most of them are missed in post-chemotherapy RPLNDs. The majority of patients exhibit normal or slightly elevated β-HCG levels. N-CTTs are usually accompanied by other components of TGCT, the most common being teratoma. Despite the high survival rate of the patients, our study points to the unpredictable evolution of NCTT cases, which may concur with a high-stage or progressive disease.