Gastroduodenal fistulae and double pyloric canal.

Four cases of endoscopically proven gastroduodenal fistulae (double pyloric canal) are presented, and ten case reports in the literature are reviewed. The fistula develops from a penetrating gastric ulcer. Presumably, the ulcer becomes adherent to adjacent duodenum and penetrates further to establish a fistulous connection, which ultimately becomes lined with mucosa, creating a second pyloric canal. Fistulae between the lesser curve of the antrum and superior fornix of the duodenal bulb were the commonest (9 out of 14). Fistulae also form between the lesser curve of the body of the stomach and the duodenal bulb or fourth part of the duodenum. Gastro-gastric fistula and a fistula into the inferior fornix of the duodenal bulb from a pyloric ulcer have been described. In two of the four cases in this series fistulae had formed from the greater curve of the antrum to the inferior fornix of the duodenal bulb, an entity not previously described. Radiologic appearances may be confused with an antral carcinoma, an ulcerating carcinoma, Crohn's disease, or lymphoma. The presence of previous ulceration and evidence of scarring should aid in avoiding confusion with malignancy. The term gastroduodenal fistula is suggested to describe double pyloric canal.