The Pyloric Sphincteric Cylinder in Health and Disease

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Chapter 31 (page 152)

Chapter 31

Pyloroduodenal Fistula or Acquired Double Pylorus

Whereas a double pylorus had previously been presumed to be of congenital origin, Hansen et al. (1972) described 2 cases in which the clinical and endoscopic findings indicated that it was usually an acquired lesion. The first case was a 55 year old male with a known prepyloric gastric ulcer. Follow-up gastroscopy showed that the ulcer had perforated into the duodenum, forming a short fistulous communication between the stomach and duodenum, which had the appearance of a second pyloric aperture. In the second case a known duodenal ulcer had perforated through the pyloric ring into the stomach, with a similar result. In both cases a mucosal septum was situated between the 2 apertures.

Drapkin et al. (1974) described a case in which a deep ulcer on the lesser curvature of the "antrum" eventually perforated into the duodenal bulb, forming an acquired pyloro- duodenal fistula. At endoscopy two pyloro-duodenal openings, separated by a mucosal septum, were seen. A catheter inserted into one opening re-entered the "antrum" through the other.

Engle (1975) collected 7 cases from the literature and described another case in which a prepyloric gastric ulcer had penetrated into the duodenum. The radiological appearance was that of a short gastroduodenal fistula, extending from the distal stomach to the duodenal bulb on the lesser curvature side. The accessory canal was separated from the normal pylorus by a septum or bridge of mucosa, which conceivably could simulate a filling defect or mass lesion at a radiographic study. It was stated that cases had probably been misdiagnosed previously and that the condition was more common than the number of reported cases would suggest. A similar case was reported by Bender and Soffa (1975).

Hegedus et al. (1978) studied the developmental history as well as the clinical, endoscopic and radiological features of 11 cases of acquired double pylorus encountered among 7,932 consecutive radiographic studies over a 3 year period. They were able to show how a known prepyloric gastric ulcer penetrated the wall and eventually perforated into the duodenal bulb to form a second "pyloric canal". This left no doubt about the acquired nature of the lesion. In 7 of the patients peptic ulcer symptoms disappeared at the time of formation of the fistula, rendering surgical interference unnecessary. It was said that the gastric side of the fistula might not be visible endoscopically, as it could be covered by fibrin or necrotic material; it was easier to recognize the condition radiologically.

Tallman et al. (1979) reported another 4 cases. In the first case 2 constantly patent pyloric openings with intact mucosal margins were seen gastroscopically. The duodenum could be visualized through both channels. The patient had had a prepyloric gastric ulcer for the previous 8 years. In another case a radiographic study showed a short fistulous tract leading from the superior portion of the "antrum" to the superior fornix of the duodenal bulb. In a third case gastroscopy showed a rosary of oedematous mucosal folds; although a fistula was not visible initially, a pediatric endoscope inserted through the occluded opening entered the duodenum. Two subsequent radiographic studies failed to reveal the fistula. In the fourth case a lesser curvature prepyloric ulcer had led to 2 fistulous communications between the stomach and duodenum, resulting in a tri- channelled pylorus.

Thompson et al. (1982) estimated that approximately 60 cases had been described up to that time. The fistulous communication usually extended from the lesser curvature of the "distal antrum" to the superior fornix of the duodenal bulb; less commonly it was located on the greater curvature side. The radiological appearance was usually characteristic; endoscopy sometimes failed to diagnose the condition.

During 6810 consecutive radiographic studies over a 2 year period we encountered 5 cases of acquired double pylorus (Keet and Bezuidenhout 1984). Four will be described briefly:

Case Reports

Case 31.1. S.K., 67 year old male, was admitted with a history of burning epigastric pain of 4 months' duration. It commenced a few hours after meals, woke him at night and was relieved by food and antacids. Occasionally it radiated to the back. There was no history of haematemesis or malaena. Twenty years prior to admission he had had a bout of similar symptoms.

Physical examination revealed epigastric tenderness. A radiographic study, done elsewhere, showed an irregular narrowing 3.5 cm in length at the pylorus (Fig. 31.1A); it had been interpreted as a carcinoma. Repeat radiological examination showed that the narrowing was in reality a fistulous connection between the distal end of the pyloric sphincteric cylinder and the base of the duodenal bulb on the lesser curvature side. It was adjacent to, and located on the posterior aspect of the pylorus. The sphincteric cylinder remained partially contracted as illustrated, neither maximal contraction nor maximal expansion occurring. The duodenal bulb was deformed. The condition was diagnosed as an acquired double pylorus, i.e. a pyloroduodenal fistula as a result of a perforating ulcer. Endoscopy showed a benign pyloric ulcer filled with necrotic material. It had perforated into the duodenum and the instrument could be manipulated into the duodenum through the pylorus as well as through the channel formed by the perforation.

Fig. 31.1 A,B. Case S.K. A Narrow, irregular channel between pyloric sphincteric cylinder and duodenal bulb, diagnosed as carcinoma. Normal pyloric aperture not filled with barium. Cylinder partially contracted. B Resection specimen. Arrow through pyloroduodenal fistula. Pyloric aperture visible behind arrow

At operation considerable fibrotic reaction was encountered and the duodenum had to be dissected from the pancreas. A truncal vagotomy, antrectomy and Billroth I anastomosis was performed. The resection specimen showed a second aperture between the stomach and duodenum next to the normal pylorus, with a bridge of mucosal tissue between the 2 apertures (Fig. 31.1B) confirming the diagnosis of pyloroduodenal fistula or so-called double pylorus.

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