Histologic, Immunohistochemical, and Molecular Classification of 52 IPMNs of the Pancreas

IN pattern IPMNs were the most common. Mixed histology was common. K-ras mutations were most common, but did not correlate with dysplasia. p53 mutations were seen in 6% of cases (only in GF and PB subtypes). A HER2 mutation was found in a GF IPMN. EGFR and BRAF mutations were restricted to IN IPMNs. These findings suggest the possibility of alternate pathways for carcinogenesis between epithelial subtypes of IPMNs.