A Heterotopic Gastrointestinal Gland Polyp with a Maximum Diameter of 55 mm

Abstract

A heterotopic gastrointestinal gland polyp (HGGP) is a lesion with a polypoid morphology that indicates submucosal expansive growth and is characterized by marked cystic growth of dilated glands in the gastrointestinal submucosal layer. It is also known as hamartomatous inverted polyp (HIP) or hamartoma. A patient with a suspected gastric submucosal tumor that was found by gastrectomy to be HGGP (55mm) is presented. A 59-year-old woman had been examined at a local clinic for melena and left hypochondralgia 6 months previously, and since investigations suggested the possibility of a gastric submucosal tumor, she was referred to our hospital. Preoperative investigations did not lead to a definitive diagnosis, and laparoscopic local resection was conducted for the purpose of diagnosis and treatment. The tumor in the resected specimen measured 55×40×35 mm and weighed 32 g. It was a mucinous, multilocular cystic lesion located in the submucosa and covered in crypt epithelium. Pathological investigations showed that non-tumorous mucosa had folded inward on itself. The invaginated mucosa contained dilated glands and hyperplasic crypt epithelium and HGGP was diagnosed. Our investigation of reported cases in Japan indicated that nonpedunculated HGGP lesions in the stomach must be treated with local resection to enable full-thickness resection.