This paper concerns one of the most interesting yet controversial anatomical variations of the pylorus, namely, a protrusion of redundant gastric mucosa into the duodenum. Since first reported by Schmieden1 in 1911, the number of cases appearing in the literature has been rapidly increasing. The etiology is generally believed to be due to hypermotility of the gastric mucosa and a propulsion of this redundant mucosa through the pylorus during the course of normal peristaltic activity.
The accepted occurrence rate of prolapsed gastric mucosa is about 10% of all gastrointestinal examinations. Maurice Feldman2 reported on a survey of the literature in which the incidence varied from 0.1% to 7.7%. He personally reported 371 cases of gastrointestinal studies, with 52 cases, or 14%, showing some degree of prolapse. Rappaport and Alper's paper3 on 1000 consecutive x-ray examinations of the stomach showed 155 cases of prolapse, or 15.5%. Our studies