Intraductal papillary-mucinous tumors of the pancreas: Predictive criteria of malignancy according to pathological examination of 53 cases

Background: One of the main problems in the management and treatment of intraductal papillary-mucinous tumors is the lack of a reliable predictive factor for malignancy. Hypothesis: Surgical treatment could be adapted to macroscopic criteria (presence of mural nodules and diameter of the pancreatic duct and of the lesion) or to tumor location (main duct, branch duct, or combined lesions) associated with benign or malignant forms. Design: Retrospective study. Setting: Two university and tertiary referral centers. Patients: Fifty-three consecutive patients who underwent pancreatic resection for intraductal papillary-mucinous tumors between January 1, 1985, and December 31, 2000. Results: Macroscopic analyses of tumors showed 6 main duct lesions, 12 branch duct lesions, and 35 combined lesions. A carcinoma was present in 33 cases (62%): 22 (41%) were invasive and 11 (21%) were noninvasive; 9 (17%) were borderline tumors and 11 (21%) were benign. Carcinoma and invasive carcinoma forms were less frequent in branch duct lesions (P<.001 and P=.009, respectively). Mural nodules were more frequent in carcinomas (P=.006) and invasive carcinomas (P<.001), with a positive predictive value of malignancy of 81%. The diameter of lesions (branch duct lesion ≥30 mm) or main duct (main pancreatic duct ≥15 mm in combined or main pancreatic duct lesions) did not correlate with malignancy. Conclusions: No carcinoma occurred in branch duct types smaller than 30 mm without mural nodules. Limited resection may be appropriate only in this type of tumor.