Natural course of autoimmune pancreatitis without steroid therapy showing hypoechoic masses in the uncinate process and tail of the pancreas on ultrasonography

Autoimmune pancreatitis, a unique form of chronic pancreatitis, is characterized by irregular narrowing of the pancreatic duct, swelling of the parenchyma, lymphoplasmacyte infiltration and fibrosis, hyperglobulinemia, positive autoantibody test results, and effectiveness of steroid therapy. Although autoimmune pancreatitis has become widely recognized as a new clinical entity of the pancreatic diseases, and several authors have reported patients with autoimmune pancreatitis, particularly in Japan, to our knowledge, the imaging findings of the natural course of autoimmune pancreatitis without steroid therapy have not been described previously. In addition, few cases of autoimmune pancreatitis show separated plural pancreatic lesions. We describe a case of autoimmune pancreatitis found incidentally that showed separated plural pancreatic lesions and that was followed without steroid therapy. © 2006 by the American Institute of Ultrasound in Medicine.