Intraductal Mucin - Hypersecreting Neoplasm of the Pancreas : US , CT and ERP Findings

Purpose: To eva1uate US, CT and endoscopic retrograde pancreatography (ERP) findings ofintrad ucta1 mucin-hypersecreting neop1asm (IMHN). MateriaJs and Methods : We categorized an IMHN as be10nging to a group of disease that can be clinica11y detected by the pooling ofmucus prod uced by tumors inside the main duct or branch ducts ofthe pancreas, thus causing di1atation ofthese ducts. We retrospective1y reviewed the US , CT and ERP findings offive patients(hyperp1asia, 4 ; adenocarcinoma, 1). ResuJts : On US and /or CT, diffuse di1atation of the main pancreatic duct was demonstrated in five patients. In two cystic 1esions corresponding to cystic dilatation of branch ducts were noted at the pancreatic head(n= 1) and neck(n= 1). In one patient, mu1tip1e cystic 1esions were seen on CT a10ng the entire pancreas, but these were not detected on US . In a11 patients, dilatation ofthe main duct and/or its branch ducts was seen on ERP. Filling defects resulting from mucin in the main duct or branch ducts were noted in a11 cases. Lymphadenopathy was not seen on US or CT, but carcinoma peritonei was found in the adenocarcinoma patient at the time of operation. ConcJ usion : IMHN usually shows smooth , diffuse di1atation ofthe main duct, and on US or CT, dilated branch ducts are occasionally noted. ERP findings are the most characteristic and conclusive; di1atation of the main duct and/or branch ducts is noted , with a filling defect corresponding to mucin. If overlooked during diagnosis, an IMHN might be interpreted simp1y as chronic pancreatitis, and so the recognition of this neop1asm is important.