Fusion anomalies of the pancreatic ductal system differentiation from pathologic states.

If fusion of the ventral and dorsal pancreatic ducts does not occur during fetal life, endoscopic retrograde cannulation of the papilla of Vater will visualize a small complete ductal system which is confined to the head of the pancreas. This system is characterized by normal arborizations throughout, relatively small duct diameters and the absence of a communication with the minor papilla. In contrast, if fusion has taken place and the ductal system is shortened by disease, pancreatography will demonstrate abrupt proximal termination or proximal tapering without side branches, and may show a significant duct of Santorini. If the ducts have fused, an area of narrowing approximately 3-20 mm in length commonly occurs at the level of fusion. This should not be confused with pathologic ductal stenosis.