Surgical experiences of intraductal papillary mucinous neoplasms of the pancreas at a single Japanese institute: characteristics of malignant histology.

BACKGROUND/AIMS Characteristics of intraductal papillary mucinous neoplasms of pancreas (IPMN) have been clarified by a worldwide survey and meeting. However, the malignant behavior or prognosis of the disease is not always uniform. METHODOLOGY We examined the clinicopathologic demographics, surgical records and outcome according to degree of histologic malignancy in 18 IPMN patients between 1994 and 2006. RESULTS Main duct type was observed in 3 patients, branch duct type in 6, and mixed type in 9. Eight of 18 patients (44.4%) had other malignancies, and other synchronous tumors were observed in the adenoma group. CA 19-9 was increased in invasive carcinomas. The size of the main pancreatic duct and cysts were not correlated with degree of malignancy. Mural nodules were more frequently observed in minimally invasive and invasive carcinomas. Segmental resection or observation was selected in the adenoma group; however, combined resection of main vessels was performed in invasive carcinoma groups. Although 3 of 5 patients with invasive carcinomas had a recurrence and poor patient prognosis, recurrence was not observed in other groups. CONCLUSIONS Surgical results for IPMN were satisfactory; however, it is necessary to determine the operative indication before the carcinoma becomes invasive as such lesions have a poor prognosis.