Pseudointraductal papillary mucinous neoplasia caused by microscopic periductal endocrine tumors of the pancreas: a report of 3 cases

• Published in: Human pathology Vol. 42; no. 7; pp. 1034 - 1041
• Main Authors: Kenney, Barton, MD, Singh, Gayatri, MBBS, Salem, Ronald R., MD, Paterno, Flavio, MD, Robert, Marie E., MD, Jain, Dhanpat, MD
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-07-2011; Elsevier; Elsevier Limited
• Subjects: Adenocarcinoma, Mucinous - pathology; Aged; Biological and medical sciences; Carcinoma, Papillary - pathology; Diagnosis, Differential; Female; Gastroenterology. Liver. Pancreas. Abdomen; Humans; Intraductal papillary mucinous neoplasm; Investigative techniques, diagnostic techniques (general aspects); Liver. Biliary tract. Portal circulation. Exocrine pancreas; Medical sciences; Middle Aged; Pancreatic Ducts - pathology; Pancreatic endocrine neoplasm; Pancreatic neoplasia; Pancreatic Neoplasms - pathology; Pathology; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Tumors; Pancreatic neoplasia; Intraductal papillary mucinous neoplasm; Pancreatic endocrine neoplasm; Endocrine gland; Malignant tumor; Endocrine tumor; Case study; Anatomic pathology; Microscopy; Pancreas cancer; Digestive diseases; Endocrinology; Cancer; Pancreatic disease; Endocrine pancreas
• ISSN: 0046-8177; 1532-8392
• DOI: 10.1016/j.humpath.2010.09.018

Summary Intraductal papillary mucinous neoplasms constitute histologically distinctive pancreatic tumors characterized by cystically dilated pancreatic ducts lined by papillary epithelium, often with extensive mucin production. With increasing awareness of and vigilance for these tumors, there has been a surge in the incidence of intraductal papillary mucinous neoplasms in the last few decades. However, resections of presumed intraductal papillary mucinous neoplasms sometimes reveal other types of cystic lesions. Here we describe 3 cases of small, incidentally identified pancreatic endocrine tumors that focally compressed the main pancreatic duct and presented clinically, radiologically, and grossly as intraductal papillary mucinous neoplasm. The histology of the dilated ducts in all cases lacked convincing features of intraductal papillary mucinous neoplasm, prompting more careful examination of the specimens and eventual identification of small well-differentiated endocrine neoplasms. The constellation of findings represented by pancreatic endocrine neoplasm–associated duct stricture and dilatation can mimic intraductal papillary mucinous neoplasm clinically and pathologically. Awareness of this phenomenon can potentially avoid misdiagnosis of intraductal papillary mucinous neoplasm in such cases.