Clinicopathological features of malignant intraductal papillary mucinous tumors of the pancreas: the differential diagnosis from benign entities

BACKGROUND: The accurate differential diagnosis of malignant intraductal papillary mucinous tumors (IPMTs) of the pancreas from benign IPMTs remains unclear. HYPOTHESIS: Predictive factors for differentiating malignant IPMTs from benign IPMTs can be documented. DESIGN: Retrospective study (1999-2003). SETTING: Wakayama Medical University Hospital, Wakayama, Japan. PATIENTS: Twenty-seven consecutive patients with IPMTs (11 with adenoma, 3 with dysplasia, 5 with adenocarcinoma, and 8 with invasive adenocarcinoma) who underwent surgery were retrospectively analyzed in terms of clinicopathological features. MAIN OUTCOME MEASURE: Clinical data, preoperative imaging findings, cytology, and tumor marker level, including carcinoembryonic antigen (CEA) and carbohydrate antigen (CA19-9), in serum and pure pancreatic juice. RESULTS: In preoperative imaging findings, the mean tumor size for the malignant IPMT group (81 +/- 18 mm) was significantly larger than that for the benign IPMT group (31 +/- 4 mm) (P =.002). The mean mural nodule size for the malignant IPMT group (9.8 +/- 4.4 mm) was significantly larger than that for the benign IPMT group (3.3 +/- 5.7 mm) (P =.002). The CEA levels in pure pancreatic juice in the malignant IPMT group (3051 +/- 7556 ng/mL) were significantly higher than in the benign IPMT group (41 +/- 80 ng/mL) (P =.003), although no significant differences in cytologic analyses and CA19-9 levels in pure pancreatic juice were found between the 2 groups. CONCLUSION: Our findings suggest that tumor size larger than 30 mm, mural nodule size larger than 5 mm, and CEA levels higher than 110 ng/mL in pure pancreatic juice were predictive factors for diagnosis of malignant IPMTs.