Pancreatic intraductal papillary mucinous neoplasm with sarcomatous transformation. A case report

Mixed pancreatic epithelial and mesenchymal tumors are rare, usually invasive, entities. Intraductal papillary mucinous neoplasm (IPMN) is a precursor of invasive ductal carcinoma and shares mutations with its invasive counterparts. We report the case of a 72-year-old female with a previously undescribed sarcomatous transformation of a residual IPMN with no evidence of an invasive component. The mesenchymal component showed no heterologous differentiation. Both the epithelial and the mesenchymal populations showed aberrant expression of p53 protein and the same point mutation in KRAS gene. After a 6 month follow up, there were no signs of local or distant relapse. The present case suggests that sarcomatous transformation is possible in non-invasive, intraductal pancreatic lesions.