Objective To analyze the clinical and ultrasonographic imaging features of intraductal papillary mucinous neoplasm (IPMN) of the pancreas. Methods Twelve patients with IPMN underwent surgery between May 2005 and December 2008

including 4 (33.3%) with adenoma and 8 (66.7%) with adenocarcinoma. IPMN was classified preoperatively into 3 types based on sonographic findings of different sites: main duct

branch duct

and combined type. All clinical presentations and ultrasonographic findings of those patients were reviewed and the correlation between ultrasonographic findings and histopathological results was analyzed. Results There were 9 men and 3 women with a mean age of 60.1∓9.6 years (range

32-73). Of all the 12 patients with IPMN

9 (75.0%) had experienced some symptoms of epigastric discomfort and/or pain as well as backache; 7 cases were with medical history of acute pancreatitis

5 cases with diabetes

4 cases with elevated CA19-9

and 2 cases with steatorrhea. All lesions of IPMN have been revealed by transabdominal ultrasonography. The mean diameters of the lesions were 1.4∓0.8 cm (range

0.5-2.0) and 6.3∓6.0 cm (range

2.0-20.0) in adenomas and adenocarcinomas

respectively. And the mean diameters of the main duct in adenomas and adenocarcinomas were 1.0∓0.8 cm and 1.6∓1.0 cm

respectively. Among the 4 adnomas

3 (75.0%) cases were classified as branch type based on sonographic findings

and 2 were demonstrated as mural nodules in which no color signals was detected. Among the 8 adenocarcinomas

5 (62.5%) cases were classified as main duct type

and 3 (37.5%) as combined type. In 7 of the 8 adenocarcinomas

mural nodules were detected within the dilated ducts or cysts of the lesions in which color flow signals were detected. Conclusions Transabdominal ultrasonography can reveal the pancreatic cystic lesions of IPMN as well as dilated pancreatic ducts. Some characteristics should be noticed as suggesting the possibility of malignancy: clinical symptoms of pancreatic insufficiency

large tumor size

and mural nodules with color Doppler flow signals. Transabdominal ultrasonography could be a useful tool to help diagnose and make appropriate management of IPMN.