Simultaneous early gastric cancer in identical twins: report of a case.

We report the unusual case of identical male twins developing early gastric cancers that were found almost simultaneously. A 39-year-old man underwent a barium-swallow examination to investigate the cause of right hypochondrial discomfort; the examination revealed evidence of gastric cancer in the upper body of the stomach. A diagnosis of adenocarcinoma was confirmed by endoscopic biopsy, and a total gastrectomy was performed. Subsequent screening of the patient's asymptomatic identical twin revealed gastric cancer in the lower body of the stomach, for which distal gastrectomy with Billroth I reconstruction was performed. The histopathological types of the two cancers were similar and both had infiltrated the submucosa. The relevant etiological factors contributing to the development of gastric adenocarcinoma in these identical twins is discussed, following the case report.