A Vanishing Heterogeneous Mass Arising From the Antrum: Ectopic Pancreatitis Masquerading as Malignancy

Abstract

Ectopic pancreas, also known as pancreatic rest is defined as pancreatic tissue without vascular or anatomic communication with the main body of the pancreas. This case highlights the importance of a broad differential to abdominal pain and the work-up of a unique case of pancreatic rest masquerading as neoplasm and infection. A 32-year-old woman with a history only significant for B12 deficiency and travel to Singapore, Taiwan and Cuba who presented with gradually worsening epigastric discomfort, with transition to abdominal pain, nausea and vomiting. On admission, the patient was clinically stable, with vital signs of normal limits. Physical examination revealed tenderness to palpation and guarding in the right upper quadrant and epigastrum without peritoneal signs. Serum laboratory tests were significant for a leukocytosis (17.7x103 white cells per cubic millimeter) with a predominance of neutrophils (80%). Computerized tomography showed a 9.5cm complex, partially cystic mass at the gastroduodenal junction with thickened gastric wall and distorted 1st and 2nd portion of the duodenum. Endoscopic ultrasound with fine needle aspiration demonstrated a heterogeneous mass of 5 cm arising from the antrum, with normal appearance of the pancreas, and growth of mixed gram-positive flora. Duodenal perforation was suspected, she was started on antibiotics and offered surgical exploration, which she declined and presented to another hospital for a second opinion. Repeat CT showed improvement in the size of the mass with a 1cm cystic focus in the gastric antrum ([email protected]@@gure A). Post discharge, upper endoscopy, showed no fluid collection, mass or abscess where that had previously been a mass. However, a 12x9 mm heterogeneous lesion was seen arising from the second layer of the gastric wall in the antrum, consistent with pancreatic rest ([email protected]@@gure B). The patient was diagnosed with pancreatitis and a peri-pancreatic abscess occurring in the ectopic pancreatic tissue. The patient was discharged home with no further intervention. Infection or inflammation of ectopic tissues is an easily missed diagnosis that can lead to unnecessary malignancy work-up and surgery, as nearly occurred in this patient. Diagnosis is further made difficult because fine needle aspiration is superficial and results routinely show normal gastric biopsy, as was seen in our patient. Ectopic pancreas is an important consideration to prevent unnecessary work up and shorter hospitalization time for patients.1288_A.tif Figure 1: Computerized tomography of the abdomen showing improvement in the size of the original mass with a peripherally enhancing 2.1 cm fluid collection adjacent to the gastric antrum with mural thickening, as well as a 1 cm cystic focus in the gastric antrum.1288_B.tif Figure 2: Endoscopy with evidence of 12x9 mm heterogeneous round lesion arising from the second layer of the gastric wall in the antrum, consistent with pancreatic rest. The remainder of the pancreatic parenchyma was well seen without evidence of calcification, mass, chronic pancreatitis or any cystic lesion. Complete endoscopy showed no fluid collection, mass or abscess where there had previously been a large mass.