Hamartomatous inverted polyp successfully treated by endoscopic submucosal dissection.

We report a case of gastric hamartomatous inverted polyps that are a rare histological type of gastric polyp and difficult to diagnose. Gastric submucosal tumor was detected by upper gastrointestinal X-ray series in 37-year-old man. Endoscopy revealed a submucosal tumor (SMT) , which eroded with a depression on its surface in the fornix. Endoscopic ultrasonography showed a heterogeneous tumor in the third layer. Endoscopic submucosal dissection (ESD) was performed to resect the tumor completely. The pathological diagnosis was a gastric hamartomatous inverted polyp. The patient was later discharged without any complications. Hamartomatous inverted polyps without a stalk are classified as the SMT type because the tumor is inverted down growth into the submucosal layer, otherwise polyps with a stalk are classified as the polyp type. All of the polyps were resected endoscopically, however, surgical resection was performed for those of the SMT type, because it is difficult to remove this type completely by en-block resection using conventional EMR technique. ESD method may be indicated for SMT-type hamartomatous inverted polyps.