Pancreatic intraepithelial neoplasia

A) Normal interlobular duct. B) Pancreatic intraepithelial neoplasia (PanIN)-1A with non-papillary mucinous epithelium. C) PanIN-1B with papillary epithelium. D) PanIN-2 with moderate dysplasia, right, and normal ductal epithelium, left. E) PanIN-3 with severe dysplasia. Note that, under current classification systems, B, C, and D would now all be classified as low-grade PanIN; E would be called high-grade PanIN. Hematoxylin and eosin-stained sections.