Adult hypertrophic pyloric stenosis that improved by spontaneous double channel pylorus formation.

Adult hypertrophic pyloric stenosis (AHPS) is a rare disease and presents as pyloric obstruction. Double pylorus is also a rare condition due to a gastroduodenal fistula connecting from the gastric antrum to the duodenum. A 42-year-old woman without a history of vomiting in infancy presented with postprandial abdominal distension and repeated vomiting. Abdominal computed tomography showed gastric dilatation and wall thickening of the distal stomach. Endoscopy and contrast gastrography revealed gastric outlet obstruction due to stenosis and an ulcer in the antral and pyloric region. Endoscopic ultrasonography revealed circumferential thickening of the muscularis propria layer of the pylorus. Her symptoms improved with treatment consisting of drainage, fasting, and a proton pump inhibitor. Two weeks after onset, follow-up endoscopy revealed a healing ulcer and double channel pylorus. Based on her clinical course and findings of clinical images, she was diagnosed with gastric outlet obstruction due to AHPS that was improved by double channel pylorus formation. In conclusion, AHPS that was improved by double channel pylorus formation is an extremely rare condition, and we should be aware of this disease entity.