Diagnosis of annular pancreas with endoscopic retrograde cholangiopancreatography.

Two patients with annular pancreas are described. The diagnosis was established unequivocally with endoscopic retrograde cholangiopancreatography before operation. In both patients there was pancreatitis of the annular pancreas. The first patient also had congenital absence of the ventral pancreas and pancreatic insufficiency. The second patient subsequently developed gastric outlet obstruction. The literature is reviewed.