ERCP in a patient with autoimmune pancreatitis

ERCP of a 19-year-old male with recurrent pancreatitis, elevated IgG4 suggesting the autoimmune form, and diffuse "sausage-shape" pancreas on imaging.
(A) Cholangiogram revealing a distal common bile duct stricture (arrow) with mild proximal dilation.
(B) Cholangiogram revealing diffuse intrahepatic ductal strictures (dashed arrows) with mild proximal dilation.
(C) Pancreatogram showing diffuse narrowing with areas of ductal dilation.
After initiation of prednisone, repeat imaging and IgG4 both normalized.