During a cholecystectomy for stones, an unusual lesion mimicking a neoplasm was found in a 40-year-old man. The lesion was resected using an endoscopic stapler, and the histologic diagnosis was Meckel's diverticulum with chronic inflammation and calcification of the diverticular wall. It is possible that the diverticulum had been responsible for abdominal pain in this patient, in whom it had an atypical appearance.