Figure 2.

Dual model of pancreatic carcinogenesis. The well-known precursor lesions (PanIN, IPMN and MCN) show a ductal phenotype. However, it seems now plausible that pancreatic ductal adenocarcinoma can directly originate from the centroacinar-acinar compartment through atypical flat lesions without the intermediate step of pancreatic intraepithelial neoplasia (PanIN) (acinar-ductal carcinogenesis). MCN: Mucinous cystic neoplasm; IPMN: Intraductal papillary mucinous neoplasm; ADM: Acinar ductal metaplasia; TC: Tubular complexes; MTC: Mucinous tubular complexes; AFL: Atypical flat lesion.