Pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma is a cancer of the pancreas, and specifically of its exocrine compartment, the part of the organ that makes substances and sends them out through ducts, which are thin tubes. The tumor doesn't start just anywhere: it starts in the cells that line the inner wall of those ducts, and that's where the word ductal comes from. Think of the plumbing in a house: what gets sick isn't the liquid running through the pipe, it's the layer of cells lining the pipe itself.

When someone says "pancreatic cancer," they're almost always talking about this one, because it's the most common type and accounts for the vast majority of tumors that begin in the exocrine pancreas. Other tumors start there too, the pancreatic neuroendocrine tumors, but they come from a different population of cells, so they're counted separately: they share the organ, not the disease.