LAUSR

Segmental absence of intestinal musculature (SAIM) is a rare cause of spontaneous perforation in neonates [1] and is quite rare in adults [2]. Since 2020, SAIM has been reported to cause perforation during endoscopic submucosal dissection (ESD) of the esophagus [3–5]; however, SAIM has never been reported in the stomach in adults. Herein, we report a case of SAIM identified during gastric ESD. An 83-year-old woman underwent gastric ESD for two lesions (20-mm 0-IIa + IIc and 10-mm 0-IIa) that were located on the greater curvature of the gastric antrum (▶Fig. 1 a). Both procedures were performed using a needle knife (KD-1 L-1; Olympus, Tokyo, Japan) and an IT knife-2 (KD-610 L; Olympus), and with the use of carbon dioxide insufflation. After an incision had been made around a quarter of the circumference on the distal left side, we noticed that the submucosal area moved roughly synchronously with the patient’s respiration (▶Video 1). Yellow tissue was observed through a relatively transparent submucosal layer, and was suspected to be fatty tissue outside of the stomach. The submucosal layer was easily retracted into the internal lumen by endoscopic aspiration. From the above findings, SAIM was strongly suspected. We carefully dissected the shallow layer Video 1 Segmental absence of intestinal musculature is identified in the stomach of an adult during gastric endoscopic submucosal dissection.