Predictive factors for malignancy in intraductal papillary-mucinous tumours of the pancreas

Background: Preoperative assessment of the likelihood of malignancy in intraductal papillary-mucinous tumour (IPMT) of the pancreas is often difficult. Predictive factors for malignancy and invasive carcinoma in IPMT were analysed. Methods: Sixty-two patients with IPMT underwent surgical treatment, with histological confirmation of adenoma in 28, carcinoma in situ in 14 and invasive carcinoma in 20. Tumours were of the main duct type in 14 patients, branch duct type in 32, and combined type in 16. A multivariate analysis of 17 potential predictive factors, including preoperative clinical and imaging findings, was conducted. Results: Multivariate analysis identified two independent predictive factors for malignancy: mural nodules and main pancreatic duct diameter of 7 nun or more. Mural nodules in the main duct or combined type, and mural nodules and tumour diameter of 30 nun or more in the branch duct type were particularly indicative of malignancy. Mural nodules, jaundice and main duct or combined type were predictors of invasive carcinoma in the multivariate analysis. Conclusion. The above factors should be considered in the diagnosis of IPMT to facilitate appropriate management.