“…The most universally accepted classifications are those of Danikas et al, and Zarineh et al classified AHPS into three types: type 1, which is childhood AHPS diagnosed at a late stage; type 2, which is the most common type, which occurs during adult life and is probably secondary to underlying gastrointestinal pathologies, such as peptic ulcer, malignant tumors and certain inflammatory diseases; and type 3, which is idiopathic adult-onset AHPS. 9,10 Zarineh et al divided AHPS into primary, which has no underlying cause and under which idiopathic AHPS would be classified, and secondary, caused by an underlying disorder such as excessive healing of gastric or duodenal ulcers, malignant tumors, GISTs, postoperative intraabdominal adhesions, bezoars, and increased vagal activity, causing hypertrophy of the pylorus. 2 The secondary type of AHPS usually demonstrates predominantly localized replacement by fibrous tissue, with little or no smooth muscle hypertrophy.…”