INTRADUCTAL PAPILLARY MUCINOUS TUMORS OF THE PANCREAS - IMAGING STUDIES AND TREATMENT STRATEGIES

Objective We analyzed clinicopathologic and imaging features and the p rognosis of intraductal papillary mucinous tumor (IPMT) of the pancrea s to identify imaging findings indicative of malignancy and to establi sh the optimal treatment strategy.Summary Background Data In IPMT, pre operative differentiation between adenoma and adenocarcinoma is often difficult, Appropriate treatment based on pathologic study and surgica l outcome has not been adequately documented. Methods Forty-one patien ts with IPMT underwent surgery; 15 with adenoma and 26 with adenocarci noma; main duct type in 13, combined type in 12, and branch duct type in 16. Results In malignant IPMT, deep invasion was found in 62% and l ymph node metastasis in 23% (peripancreatic nodes in 19% and distant n odes in 4%). Tumors with mural nodules (86%) had a significantly highe r incidence of carcinoma than tumors without nodules (37%), IPMT with a main pancreatic duct greater than or equal to 15 mm or tumor diamete r greater than or equal to 30 mm (branch duct type) showed a high prev alence of adenocarcinoma. Main duct (54%) and combined (58%) type tumo r, and tumors with mural nodules (64%) often showed invasion. All five branch duct tumors less than 30 mm without nodules were adenomas. How ever, imaging studies could not definitely distinguish adenocarcinomas from adenomas. Complete resection was possible for all adenomas and 8 8% of adenocarcinomas. Five-year survival rates for patients with aden omas and adenocarcinomas were 100% and 82%, respectively. Conclusions IPMT has a favorable prognosis, regardless of deep invasion or node me tastasis. IPMT requires peripancreatic node dissection in addition to complete tumor excision. Node dissection may be omitted for branch duc t tumors less than 30 mm without mural nodules.