Vancouver, Canada

Recurrent ectopic pancreatitis of the jejunum and mesentery over a 30-year period

John CT Wong, Charlotte Robinson, Edward C Jones, Alison Harris, Charles Zwirewich, Robert Wakefield, Richard K Simons and Eric M Yoshida

Vancouver, Canada

BACKGROUND: Ectopic pancreas is defined as pancreatic tissue found outside its usual anatomical position, with no ductal or vascular communication with the native pancreas. We describe a case of ectopic pancreas of the small bowel and mesentery causing recurrent episodes of pancreatitis, initially suspected on computed tomography (CT) and magnetic resonance cholangiopancreatography (MRCP), and confirmed on histological review of the resection.

METHODS: A 67-year-old woman presented with clinical symptoms and biochemical evidence of pancreatitis. She had similar episodes over the past 30 years with unrevealing investigations, and was concluded to have idiopathic pancreatitis. She underwent CT and MRCP, with findings suggestive of ectopic pancreas, a diagnosis confirmed on histology of the resection.

RESULTS: MRCP identified a mass in the proximal small bowel mesentery isointense to the native pancreas, with a small duct draining into a proximal jejunal loop. The resected specimen consisted of normal parenchyma with lobulated acinar tissue with scattered islets of Langerhans, an occasional ductular structure, and admixed areas of adipose tissue. The patient remained asymptomatic with normal biochemistry six months post-operatively.

CONCLUSION: In an individual with abdominal pain, elevated serum amylase/lipase, but imaging findings of a normal native pancreas, ectopic pancreatitis should be considered, and can be evaluated by CT and MRCP.

(Hepatobiliary Pancreat Dis Int 2011; 10: 218-220)

ectopic pancreas; gastrointestinal tract; endoscopic ultrasound; computed tomography; magnetic resonance cholangiopancreatography

Introduction

Ectopic pancreas (EP) is defined as pancreatic tissue found outside its usual anatomical position, with no ductal or vascular communication with the native pancreas. This congenital entity is an underrecognized cause of common clinical presentations such as pancreatitis, obstruction and gastrointestinal bleeding.[1-4]Our patient is the first reported case of EP of the small bowel and mesentery causing recurrent episodes of pancreatitis, suspected on magnetic resonance cholangiopancreatography (MRCP) and confirmed on histological review of the resection.

Case report

A 67-year-old woman presented to the Emergency Department after three days of postprandial epigastric stabbing pain radiating to the back, accompanied by nausea and vomiting but no hematemesis, and with no relief from ranitidine (her only medication, prescribed for intermittent "dyspepsia"). Her past medical history included only a laparoscopic cholecystectomy, and she consumed no alcohol.

Similar episodes had recurred over the past 30 years, with the most recent three years ago when serum lipase was ＞2300 U/L (normal 0-400 U/L) with no evidence of pancreatitis on abdominal computed tomography (CT). Each of these incidents resolved clinically and biochemically with bowel rest, intravenous fluid administration and analgesia.

On examination of the abdomen, a laparoscopic scar was noted, and tenderness was localized to the epigastrium.

Fig. 1. A, B: Axial and coronal slices of a contrast-enhanced abdominal CT demonstrating perijejunal ectopic pancreatic tissue with surrounding peripancreatic inflammatory changes (arrow). C: MRCP showing presence of a duct (small straight arrow) originating from ectopic pancreas (large straight arrow), distinctly separated from but isointense with the native pancreas and its associated duct (curved arrow).

Fig. 2. Intra-operative photo demonstrating a 6.5-cm long, 2.5-cm wide and 1.6-cm deep indurated teardrop-shaped mass (tip of hemostat), at the junction of the duodenum and jejunum, with a tail extending down to the root of the mesentery.

The hematological profile, serum calcium, creatinine, urea, liver enzymes and triglycerides were all normal. Serum lipase was ＞3000 U/L. Abdominal CT examination with intravenous contrast showed normal enhancement of the orthotopic pancreas with no pancreatic duct dilation or peripancreatic inflammatory changes. However, a mass of putative ectopic pancreatic tissue was identified in the proximal small bowel mesentery, arising from the proximal jejunum, with surrounding inflammatory changes in the mesenteric fat (Fig. 1A, B). A small ductal structure was evident within the EP, communicating with the adjacent jejunal loop. MRCP demonstrated the ectopic pancreatic tissue to be isointense to the native pancreas, with a small duct draining into a proximal jejunal loop (Fig. 1C). There was no continuity between the native biliary system and the EP.

Due to recurrent episodes requiring medical care, the patient underwent laparotomy. A mass was visualized within the jejunal mesentery with a tail extending down to the mesenteric root (Fig. 2). The mass with the overlying adherent jejunum was resected. Histologically, the specimen showed ectopic pancreatic tissue, involving the muscularis propria and adventitia of the jejunum. The pancreatic tissue consisted of normal parenchyma with lobulated acinar tissue with scattered islets of Langerhans, an occasional ductular structure, and admixed areas of adipose tissue. The latter had focal fat necrosis with adjacent chronic active inflammation. At the interface of the EP with the mesenteric fat there was reactive fibrosis. There was no hemorrhage.

The patient remained asymptomatic with normal biochemistry six months post-operatively.

Discussion

The prevalence of EP among adults has been reported as high as 15%.[5]Embryologically, the native pancreas develops from endodermal evaginations of the primitive duodenal wall. EP may represent evaginations that became separated from the main body with distant transport during longitudinal intestinal growth.[6]EP has been described predominantly within the submucosa of the stomach, duodenum and jejunum. EP can present with complications shared by the native pancreas (i.e. pancreatitis, pseudocyst formation).[1]Alternatively, symptoms like obstruction and bleeding are secondary to its anatomical location, size and endocrine/exocrine secretions.[2-4]Until recently, most cases of EP were diagnosed post-laparotomy on histological examination of the resected specimen, usually suspected preoperatively as gastrointestinal stromal tumor, lymphoma or small bowel tumors. New diagnostic features on endoscopic ultrasound and computed tomography have been identified.[7,8]EP on histology is categorized according to the modified von Heinrich's classification.[9]There are no consensus guidelines on the management of symptomatic EP, but both resection and conservative management have been advocated. The decision tointervene therefore depends on the frequency and severity of the patient's symptoms and their comorbidities. EP is an under-recognized congenital entity with a myriad of clinical presentations that at present may be more frequently diagnosed noninvasively by endoscopic ultrasound, computed tomography and magnetic resonance cholangiopancreatography. Ectopic pancreatitis should be considered in an individual with abdominal pain, elevated serum amylase/lipase, but imaging findings of a normal native pancreas.

Funding: None.

Ethical approval: Not needed.

Contributors: WJCT, WR and SRK were primarily involved in the clinical care of the patient; RC, HA and ZC interpreted the radiographic imaging; JEC reviewed the pathology of the resected specimen; WJCT and YEM wrote the manuscript. All authors have reviewed and approved the final version of this manuscript. YEM is the guarantor.

Competing interest: No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.

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Received April 27, 2010

Accepted after revision December 11, 2010

Author Affiliations: Department of Medicine (Wong JCT and Wakefield R), Department of Radiology (Robinson C, Harris A and Zwirewich C), Department of Pathology and Laboratory Medicine (Jones EC), Department of Surgery (Simons RK), Division of Gastroenterology, Department of Medicine (Yoshida EM), 2775 Laurel Street, University of British Columbia, Vancouver, British Columbia, Canada, V5Z 1M9

Eric M Yoshida, MHSc, MD, Professor and Head, Division of Gastroenterology, Department of Medicine, University of British Columbia, 5th floor Gordon and Leslie Diamond Health Care Center, 5153-2775 Laurel Street, Vancouver, British Columbia, Canada (Tel: +1-604-875-5371; Fax: +1-604-875-5447; Email: eric.yoshida@vch.ca)

? 2011, Hepatobiliary Pancreat Dis Int. All rights reserved.