Significance of the site of origin of pancreatic exocrine adenocarcinoma.

The pancreatic head and neck constitute less than half (mean 46 +/- 5%) of the whole pancreas. There is no difference in the concentration of ductal epithelium between the head and the body of the pancreas. The preponderance of pancreatic exocrine tumours which arise in the head of the pancreas compared to the body is not, therefore, due to a larger number of cells at risk in the pancreatic head. This suggests that there is a greater risk of exocrine adenocarcinoma developing from the cells within the head of the pancreas than in those within the body of the pancreas.