A Case of Segmental Absence of Intestinal Musculature Associated With a Gastric Diverticulum in an Adult.

A man in his late 50s underwent an abdominal computed tomography (CT) scan as part of a whole-body trauma assessment after a bicycle accident. Incidentally, a mass was detected between the left adrenal gland and the posterior wall of the gastric fundus. Given the differential diagnosis of either an adrenal tumor or a gastric diverticulum, laparoscopic resection was planned. Intraoperatively, the mass was identified as a gastric diverticulum, and a partial gastrectomy was performed. Histopathological examination revealed no abnormalities in the mucosa or the muscularis mucosae. However, the muscularis propria was markedly thinned and partially absent. There was no evidence of necrosis or inflammation. These findings are consistent with the segmental absence of intestinal musculature (SAIM) of the stomach. To our knowledge, this is the first reported case of SAIM of the stomach associated with a gastric diverticulum in an adult.