Gastric Adenocarcinoma at the Anastomotic Site Three Decades after Gastrojejunostomy: A Case Report with Literature Review.

Malignancy at the gastrojejunostomy site, though rare, is a recognized long-term risk factor of the procedure. Such malignancies, though uncommon, pose diagnostic and therapeutic challenges. We report a case of a 63-year-old male presenting with a rare complication of gastric carcinoma at the loop gastrojejunostomy site 30 years after surgery for duodenal ulcer-induced gastric outlet obstruction. The patient's symptoms included chronic intermittent upper abdominal pain, postprandial bilious vomiting, significant weight loss, and anorexia. The diagnosis was established through imaging and endoscopic biopsy, revealing a poorly differentiated carcinoma. Following preoperative optimization, the patient underwent subtotal radical gastrectomy with Roux-en-Y reconstruction with D2 lymphadenectomy. Histopathology confirmed poorly cohesive gastric carcinoma (signet ring cell type) with extensive lymph node metastasis (pT4a pN3a M0). Postoperative recovery was uneventful, and the patient was discharged on a CAPEOX regimen for adjuvant chemotherapy. This case highlights the importance of vigilance in patients with long-standing gastrojejunostomy, given the risk of malignancy at the anastomotic site.