Beyond the Gonads: A Rare Encounter with an Intra-abdominal Germ Cell Tumor

This case report details a rare presentation of an extragonadal germ cell tumor (GCT) involving the jejunum and mesentery in a 47-year-old male. The patient presented with abdominal pain and weight loss, and imaging revealed a hypermetabolic mesenteric mass with atypical features. The diagnosis was established through histopathology, immunohistochemistry, and elevated α-fetoprotein and lactate dehydrogenase levels, confirming a non-seminomatous GCT. Initial chemotherapy was modified due to biochemical progression, and follow-up imaging showed marked tumor regression. Despite treatment, the patient succumbed to complications. This case underscores the diagnostic complexity and rarity of intra-abdominal extragonadal GCTs, which can mimic other malignancies both radiologically and clinically. It highlights the importance of integrating radiological, serological, and histopathological data for accurate diagnosis and effective management. Clinicians should consider extragonadal GCTs in the differential diagnosis of unusual abdominal masses, particularly when tumor markers are elevated.