Primary Yolk Sac Tumor of the Stomach in a 2-Year-Old Boy: Case Report on a Rare Site for Extragonadal Malignant Germ Cell Tumor.

Up to one-third of germ cell tumors are extragonadal neoplasms, with yolk sac tumors (YSTs) being the most common malignant histology. This report describes the successful multimodal management of a primary YST of the stomach in a 2-year-old boy. The child presented with melena, and further evaluation revealed a mass lesion in the cardia of the stomach. A biopsy established a diagnosis of a YST, which correlated with an elevated serum alpha-fetoprotein level. The child received three cycles of chemotherapy consisting of cisplatin, etoposide, and bleomycin (PEB), followed by surgical resection in the form of proximal gastrectomy. After an uneventful recovery from surgery, he received an additional three cycles of PEB and has remained disease-free for 7 years. This case highlights the potential for the occurrence of a relatively rare childhood tumor at an unusual site, which can pose diagnostic challenges. However, careful evaluation and meticulous management can lead to favorable outcomes.