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Answer: Papillary Low-Grade Neuroendocrine Tumor of the Pancreas With Pancreatic Duct Dilation
Figure 1. Axial magnetic resonance image of the abdomen demonstrating large pancreatic ductal dilation without obvious mass.
Figure 2. Intraoperative photograph demonstrating an enlarged main pancreatic duct (black arrows) and enlarged peripheral pancreatic ducts (white arrows).
Prominent pancreatic duct dilation with a mass lesion within the head of the pancreas has been found to represent a primary adenocarcinoma of the pancreas in most patients. These patients are also found to have concomitant biliary dilation. Isolated significant (>2-cm) pancreatic ductal dilation has been demonstrated to occur more commonly in mucin-producing lesions of the pancreas and primarily in intraductal papillary mucinous tumors of the pancreas.1
Neuroendocrine lesions of the pancreas represent 0.5% of all pancreatic tumors.2 Approximately one third of neuroendocrine tumors are hormonally inactive and account for about 20% of all endocrine tumors of the pancreas.3 Histochemically, they are identified as insulin (50% of cases), pancreatic polypeptide (40%), glucagon (30%), and somatostatin (13%) cells. Nonfunctioning pancreatic tumors are usually unifocal, except when associated with multiple endocrine neoplasia type 1 syndrome.4 These lesions usually occur during the fourth or fifth decade of life, with an even sex distribution.5
Because these tumors remain clinically silent during their growth, they may attain great size without causing apparent clinical findings and commonly present in an advanced stage. Other forms of nonfunctioning neuroendocrine tumors, when originating in critical locations, can be found with elevated liver function test results or, as in this case, as a dilated pancreatic duct.
Patients who present with significant pancreatic ductal dilation should be examined to rule out proximal mass lesions. Most of these patients will ultimately undergo pancreaticoduodenectomy, which establishes the final diagnosis.
The Editor welcomes contributions to the “Image of the Month.” Send manuscripts to Archives of Surgery, Johns Hopkins Medical Institutions, 720 Rutland Ave, Ross 759, Baltimore, MD 21205; (443) 287-0026; e-mail: firstname.lastname@example.org. Articles and photographs accepted will bear the contributor’s name. Manuscript criteria and information are per the “Instructions for Authors” for Archives of Surgery. No abstract is needed, and the manuscript should be no more than 3 typewritten pages. There should be a brief introduction, 1 multiple-choice question with 4 possible answers, and the main text. No more than 2 photographs should be submitted. There is no charge for reproduction and printing of color illustrations.
Correspondence: Robert C. G. Martin II, MD, Department of Surgery, University of Louisville, Norton Healthcare Pavilion, Room 312, 315 E Broadway, Louisville, KY 40202 (email@example.com).
Accepted for Publication: April 28, 2003.
Image of the Month—Diagnosis. Arch Surg. 2005;140(3):312. doi:10.1001/archsurg.140.3.312
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