Aberrant Pancreatic Tissue in the Stomach

Abstract

Of the benign tumors of the stomach wall, aberrant or accessory pancreatic tissue is one which may possess a distinct characteristic, thus enabling the radiologist to suggest the correct diagnosis. Most radiologists are familiar with this entity, and there are probably unrecorded cases in which the exact diagnosis was made preoperatively. There is, however, a paucity of reported instances in which the correct diagnosis was suggested on the basis of the roentgenologic findings. It would seem, therefore, that these findings should be re-emphasized. The purpose of this report is threefold: (a) to discuss briefly aberrant pancreatic tissue; (b) to reiterate the roentgen findings of aberrant pancreatic nodules in the stomach; (c) to add 7 cases to those previously reported. Aberrant pancreatic tumors have been found not only in the stomach, but also throughout the small intestine and the transverse colon, in Meckel's diverticula, in the mesentery, spleen, gallbladder, bile ducts, liver, and mediastinum. Approximately 70 per cent are located in the stomach (1) and, of these, 85 per cent are in the antrum or pylorus. About three-fourths of these gastric nodules lie in the submucosal layers and project into the lumen. The remaining 25 per cent lie in the deeper layers and are more difficult to detect. The theories of origin may be briefly summarized as follows: (a) a transplantation of a portion of the pancreas from its original site during embryonic development; (b) metaplasia of other glands during postnatal life; (c) an atavistic phenomenon, with reversion to lower animal forms which contain pancreatic tissue in other locations. Palmer (2) in 1951 presented an extensive review of gastric heterotopic pancreatic tumors and discussed the 215 proved cases from the world literature. Since his report, at least 143 additional cases have been found in the international medical literature; only 9 of these appeared in the American radiologic journals, in two separate reports (3, 4). Other indications of the incidence of this lesion have been suggested by de Castro Barbosa and Waugh, who stated that at the Mayo Clinic aberrant pancreatic tissue is found in the abdomen about once in every 500 laparotomies. de Castro Barbosa and his associates also stated that this lesion was found in 1.7 percent of their routine autopsies between 1939 and 1943. The most common symptom usually ascribed to aberrant pancreatic tissue in the stomach is non-specific epigastric pain. Six of our 7 patients had this complaint. Seventy-five per cent of the patients that Palmer (2) evaluated for clinical data had some type of epigastric pain as the presenting symptom. Pyloric obstruction is probably the next most common symptom. This was present in 25 per cent of Palmer's adult patients, and 1 of our patients had symptoms suggestive of partial intermittent obstruction with occasional episodes of distention.