Heterotopic pancreas is defined as pancreatic tissue outside of the normal topographic boundaries of the pancreas, lacking any anatomic or vascular connections to normal pancreas. On microscopy, the tissue contains pancreatic acini, ducts, and islets of Langerhans in a normal anatomical relationship. The incidence ranges from 0.55% to 13.7% in autopsy series with reports more commonly being in the lower end of this range.1,2 The frequency at laparotomy is between 0.2% and 0.5%.3 In adulthood, the anomaly occurs most commonly in men aged 60 to 80 years.2- 4 In children, heterotopic pancreas occurs commonly in a Meckel diverticulum, and girls predominate by 2:1.4
Development of heterotopic pancreatic tissue is believed to be an error in embryological development. Tissue may separate from the pancreas during midgut rotation; alternatively, aberrant heterotopic tissue may be formed during the lateral budding of the rudimentary pancreatic duct while penetrating the intestinal wall with subsequent migration in the intestinal wall as the bowel lengthens.2,5 More than 50% of heterotopic pancreatic tissue is found in the stomach or the second part of the duodenum.1,3 Other gastrointestinal locations include the jejunum, ileum, colon, Meckel diverticulum, gall bladder, bile duct, and ampulla of Vater.1,3,4 Extragastrointestinal sites have been described in the liver, lungs, omentum, mesentery, umbilicus, mediastinum, and fallopian tube.6 The patient’s heterotopic pancreas arose from her esophagus. Only 11 cases of esophageal-associated heterotopic pancreas have been reported in the literature.6,7
Symptoms are related to the location of the heterotopic tissue. The majority of heterotopic pancreatic tissue is found in the upper gastrointestinal tract. Therefore, common signs and symptoms include epigastric pain, weight loss, hematemesis, nausea and vomiting, and jaundice.3,4,6,7 Benign pathological changes occur in the heterotopic tissue at a similar rate to that of normal pancreas. Pancreatitis, pseudocyst formation, and abnormal hormone secretion have been reported.3 Malignant changes, namely adenocarcinoma, cystadenomas, anaplastic carcinomas, and islet cell adenomas, have also been reported.3,4 Approximately 50% of lesions are symptomatic: symptoms sometimes seem to regress spontaneously, or other causes are found for the symptoms. Reports indicate a 60% success rate of relief of symptoms with surgical resection.3,4 The true incidence of heterotopic pancreas is not known, and most lesions are likely incidental findings without associated signs or symptoms.
Our patient was having repeated episodes of acute heterotopic pancreatitis. These recurrent bouts led to the severe fibrosis that we saw on pathological examination and caused the mass to be densely adherent to the liver and diaphragm.
Correspondence: Glyn G. Jamieson, MD, FRCS, FRACS, Dorothy Mortlock Professor of Surgery, University of Adelaide Department of Surgery, Royal Adelaide Hospital, North Terr, Adelaide, South Australia 5000, Australia (email@example.com).
Accepted for Publication: November 30, 2004.
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Image of the Month—Diagnosis. Arch Surg. 2005;140(5):516. doi:10.1001/archsurg.140.5.516