Intraluminal diverticulum: a form of duplication.

Abstract

Intraluminal diverticulum of the duodenum is an unusual congenital anomaly that can be readily recognized by its striking and characteristic roentgen appearance. The abnormality, which so far has been reported only in the second portion of the duodenum, consists of a pocket-like structure, open proximally and closed distally, attached to the inner wall of the gut. A portion of its wall is contiguous with that of the normal duodenum, while the remainder is formed by a thin membrane covered on both sides by typical duodenal mucosa. Although Silcock (6) demonstrated the lesion at autopsy in 1895, it was not until 1947 that Nelson (5) first described its roentgen appearance. Four additional articles on the subject have since appeared in the literature, each reporting a single case (2, 3, 4, 7). All authors except Köhler (3) have attributed the lesion to an incomplete duodenal diaphragm which has become pouch-like as a result of peristaltic activity. We believe that the embryological theory proposed by Bremer (1), to explain duplication of the intestinal tract, is equally applicable to the genesis of intraluminal diverticulum. Thus, as postulated by Köhler, this anomaly may actually represent a form of intestinal duplication rather than a distorted incomplete duodenal diaphragm. Recently we have encountered 2 patients at the University of Cincinnati Medical Center with intraluminal diverticulum of the duodenum demonstrated roentgenologically. In one, surgical correction was complicated by injury to the ampulla of Vater. Case I: I. W., a 47-year-old white male, was first seen at the Cincinnati Veterans Hospital complaining of the sensation of a lump in the epigastrium for six months. This occurred only after eating or drinking and was sometimes accompanied by nausea. The past history was non-contributory. The patient had had no gastrointestinal complaints prior to the present illness. Physical examination and laboratory studies were normal. An upper gastrointestinal series (Figs. 1A and 1B) demonstrated a peculiar defect extending from the mid-descending duodenum well into the third portion. This defect had a large, smooth lumen, the mucosa of which showed a longitudinal linear pattern. The lumen filled with barium from its proximal end. In the upright position it contained entrapped gas. The pocket-like structure impinged upon the main duodenal channel, from which it was separated by a thin, smooth radiolucent membrane. On fluoroscopy the lumen was seen to fill and empty with duodenal peristalsis. At times a mild degree of intussusception appeared to occur, but this did not reproduce the patient's symptoms. The remainder of the gastrointestinal tract was normal. At operation the duodenum appeared normal externally, but when it was opened, several large pieces of pineapple were found free in the lumen. In the distal descending and proximal transverse portions of the duodenum two separate lumens were identified. The more medial of these was about 6 cm.