Clinical quiz. Prepyloric heterotopic pancreas.

Abstract

A 2-year-old boy was referred to the Paediatric Gastroenterology Unit because of a short period of vomiting, dysphagia, and decreased appetite. He had been operated at birth for an esophageal atresia; the postoperative course and recovery had been uneventful. He remained healthy until the present episode of acute vomiting and dysphagia, which began 48 hours before referral to our unit. Physical examination was unremarkable. Complete blood count and sedimentation rate were normal. Contrast radiography of the upper gastrointestinal tract ruled out anastomotic esophageal stricture but strongly suggested the presence of a foreign body obstructing the lower esophagus. The child underwent esophagogastroscopy under general anesthesia. At esophagogastroscopy, no foreign body was present, but an ulcerative lesion of the lower esophageal region was noted, corresponding to the location of the presumed esophageal foreign body before spontaneous migration. Esophagoscopy was followed by a systematic examination of the stomach, pylorus, and duodenum. Surprisingly, a 10-mm diameter lesion was noted in the lumen of the prepyloric region (Fig. 1); the surrounding mucosa was normal. Biopsies of this lesion were performed. FIG. 1. No caption available.This lesion most likely represents: A. Gastric leiomyoma B. Heterotopic pancreas C. Peptic ulcer D. Gastric adenocarcinoma E. Gastric hyperplastic polyp Answer: B. Prepyloric heterotopic pancreas. Although definitive diagnosis is made histologically, most cases of gastric heterotopic pancreas have a unique endoscopic appearance, as in the present observation, that often makes possible a diagnosis before histologic confirmation. Gastric ectopic pancreas is recognizable as a well-defined dome-shaped firm nodule usually less than 30 mm in the gastric antrum, usually in the prepyloric region, with a central umbilication as shown in Figure 1. In our case, mucosal biopsy results were normal. Leiomyomas are often located more proximally in the fundus and are larger. Diagnosis of gastric adenocarcinoma and gastric hyperplastic polyp were ruled out according to the endoscopic appearance and the normal histologic analysis of the gastric biopsy specimens. Comment: Heterotopic or aberrant pancreas is defined as the presence of pancreatic tissue lacking anastomotic and vascular continuity with the main body of the pancreas. It is a rare congenital anomaly, incidentally found in 1% to 2% of autopsies (1). Most of the aberrant pancreases located in the upper gastrointestinal tract are found in the gastric antrum (2). In most cases, this congenital anomaly is an incidental finding. The most common clinical symptoms that have been attributed to ectopic pancreas include abdominal pain, gastrointestinal bleeding, and more severe clinical problems such as partial pyloric obstruction, pancreatitis, obstructive jaundice, and gastric or duodenal ulceration. Several cases of malignant degeneration occurring in ectopic pancreatic tissue have been reported. The preoperative diagnosis of heterotopic pancreas remains difficult despite modern diagnostic procedures. Sonography and computed tomography sometimes can indicate aberrant pancreatic duct or gastric tumor, but a definitive diagnosis is made histologically. Management remains somewhat debated; because this abnormality is largely asymptomatic, the incidental finding of such lesion does not necessary warrant surgical excision. However, some authors recommend the surgical resection of the tissue-bearing area because of potential complications, including malignant degeneration (3). In our case, surgical abstention under close observation was decided. Congenital anomalies occur in 40% to 57% of patients with esophageal atresia at presentation. The gastrointestinal system is commonly affected, and several congenital associated anomalies have been listed, such as pyloric atresia, duodenal or ileal atresia, and malrotation of the intestine. To the best of our knowledge, the combination of esophageal atresia and gastric heterotopic pancreas has not been reported previously and could be fortuitous.