One anastomosis gastric bypass (OAGB) is mainly criticized for the supposed carcinogenic effect of bile reflux on the gastric pouch mucosa.

A 56-year-old male patient presented 12 years after OAGB with a 10-month history of gradual dysphagia and vomiting. He was diagnosed with a tumor of the gastro-jejunal anastomosis, and underwent total gastrectomy with D2 lymphadenectomy. Specimen examination showed a diffuse isolated cell-type adenocarcinoma. To our knowledge, we report the first case in literature of adenocarcinoma of the gastro-jejunal anastomosis post-OAGB, and the second reported case if we include the Mason loop gastric bypass, which was the earlier version of OAGB with a different conceptual and physiological aspect.

The carcinogenic effect of bile reflux in OAGB will remain hypothetical until a detailed controlled study may prove the causality between bile reflux and gastric pouch malignancies in patients with a history of OAGB.