Diffuse cystic malformation and neoplasia-associated cystic formation in the stomach. Endosonographic features and diagnosis of tumor depth.

We have evaluated the endoscopic ultrasonography (EUS) features of cystic malformation of the stomach and the depth of associated neoplasia. We included 15 patients with multiple cystic components identified on EUS: 6 patients with multiple cysts restricted focally to gastric neoplasia and 9 patients with diffusely distributed cysts. We categorized the former findings as focal cystic malformation (FCM), and the latter as diffuse cystic malformation (DCM) of the stomach and reviewed the endosonographic features. Both FCM and DCM tended to show male preponderance and develop in older patients. Cystic changes in FCM extended from the neoplastic lesion to the submucosa regardless of the location in the stomach. Diffuse cystic malformation was located predominantly in the gastric body and mainly was shown as the thickened submucosa and/or deep mucosa with multiple cystic components. The boundary between the mucosal layer or the tumor echo and the submucosal layer was indistinct in eight patients, which led to a lower accuracy in EUS diagnosis of tumor depth. Diffuse cystic malformation has characteristic EUS features and occasionally is accompanied by gastric neoplasia. Endoscopic ultrasonography is inaccurate in determining tumor depth when multiple submucosal cysts are present.