Gastrointestinal: Gastric outlet obstruction caused by a hamartomatous inverted polyp and an ectopic pancreas.

Abstract

A 38-year-old female was referred to our hospital during pregnancy with abdominal pain. Esophagogastroduodenoscopy (EGD) revealed a submucosal tumor (SMT) with a glandular opening in the gastric antrum (Fig. 1a). An endoscopic biopsy suggested ectopic pancreatic tissue. Thus, the gastric SMT was diagnosed as an ectopic pancreas, and the patient was managed conservatively because her symptoms disappeared. One year later, she presented to our hospital with abdominal pain and vomiting. Blood tests showed serum lipase: 79 U/L (normal: 16–60), pancreatic amylase: 87 U/L (normal: 16–52), and C-reactive protein: 0.82 mg/dl (normal: 0.00–0.14). Contrast-enhanced CT revealed gastric outlet obstruction (GOO) due to pyloric wall thickening and a cystic lesion in the pyloric wall (Fig. 1b). EGD showed that the SMT had enlarged and the gastric antrum was edematous (Fig. 1c). Endoscopic ultrasonography revealed hypoechoic (4 cm) and anechoic (2.5 cm) lesions, suggesting cystic components (Fig. 1d). As the patient's symptoms persisted, laparoscopic local resection for gastric SMT was planned. However, because the inflamatric wall thickness around SMT reached to pyloric ring in intraoperative finding, laparoscopic distal gastrectomy with Roux-en-Y reconstruction was finally performed (Fig. 2a). The patient's postoperative course was uneventful. A histological examination revealed normal mucosal hyperplasia in the submucosa, which is typical of a hamartomatous inverted polyp (HIP) (Fig. 2b, 2c). Furthermore, ectopic pancreatic ducts with acinar glands were found in the submucosa (Fig. 2b, 2d). Inflammatory cells were observed in the ectopic pancreatic tissue, which suggested mild pancreatitis. Finally, this case was diagnosed as gastric HIP with ectopic pancreas. This is the first reported case of a gastric HIP with ectopic pancreas. Ectopic pancreatitis might cause GOO by enlarging gastric HIP lesions.