| [ Summary ] |
There are two postulated developmental pathways for pancreatic ductal carcinoma : 1) the adenoma‒carcinoma sequence, in which invasive carcinoma develops via an adenoma, and 2) the de novo pathway, in which adenoma formation does not precede the development of invasive carcinoma. The former pathway results in the development of intraductal papillary mucinous neoplasm (IPMN)‒ derived carcinoma, while the latter results in the development of invasive pancreatic ductal carcinoma. Early pancreatic cancer, in which a good long‒term prognosis can be expected, includes non‒invasive cancer and invasive pancreatic cancer with slight invasion. Although the extent of invasion is unspecified in pancreatic cancer with slight invasion, it is speculated that less invasion is correlated with a better prognosis. For detecting cancer with slight invasion, it is important to know that some pancreatic cancers show invasion soon after their development, while others show invasion only after extending into the pancreatic duct. Mucous cell hyperplasia is highly likely to be a precancerous lesion of pancreatic cancer. |