Extragonadal Germ Cell Tumors: A Single Institution Experience with Clinicopathological Correlation

Background. Extragonadal germ cell tumors (EGCTs) are a rare heterogeneous group of tumors without evidence of primary gonadal germ cell tumors. They account for 2%-5% of overall malignancies. EGCTs are often not clinically suspected, making them challenging for pathologists. In this retrospective observational study, we describe our institutional experience among EGCTs with clinicopathological correlation. Materials and methods. All patients diagnosed as EGCTs from January 2014 to April 2023 were collected. All relevant clinical data and serum markers were retrieved from hospital medical records. Histopathology and immunohistochemistry slides were reviewed. Results. The present study included a total of 56 patients; 34 (60%) men and 22 (40%) women with a men-to-women ratio of 1.5:1. Of them, 1 patient had congenital/neonatal EGCTs, 21 patients had prepubertal EGCTs, and 34 had post-pubertal EGCTs. The common sites included are mediastinum (45%), sacrococcyx (18%), retroperitoneum (14%), and central nervous system (12%). The other rare sites were the vagina, liver, colon, and duodenum. The common germ cell tumor included mature teratoma (34%), mixed germ cell tumor (27%), seminoma/germinoma (12%), pure yolk sac tumor (11%), immature teratoma (9%), mature teratoma with somatic tumor (5%), and embryonal carcinoma (2%). All histological diagnoses of germ cell tumors were confirmed with IHC markers like PLAP, CD117 (KIT), AFP, LIN28, CD30, and β-hCG. Pre and posttreatment serum tumor marker levels were available in 37 patients. All our treated patients had a decrease or normal tumor marker levels post-therapy. Conclusion. In our study, a heterogeneous group of germ cell tumors was seen. Most of them were seen in post-pubertal adolescents and young adults. Early intervention by platinum-based combination chemotherapy in seminoma and nonseminomatous germ cell tumors has significantly improved the prognosis of malignant EGCTs similar to their germ cell counterparts.