Extrapancreatic lesions in autoimmune pancreatitis

Abstract

Goals: To examine extrapancreatic lesions associated with autoimmune pancreatitis.

Background: Autoimmune pancreatitis is a unique clinical entity proposed recently, and is reported to occasionally be associated with other autoimmune diseases.

Study: Extrapancreatic lesions were examined clinically, radiologically, and histologically in 25 patients with autoimmune pancreatitis.

Results: Stenosis of the bile duct was observed in 22 patients (lower bile duct [n = 19], upper bile duct [n = 1], intrahepatic bile duct [n = 2]). Marked extrapancreatic bile duct wall thickening not associated with obvious cholangiographic abnormality was seen on ultrasound in 3 patients. Enlargement of the salivary glands and cervical lymph nodes was detected in 4 patients. Abdominal lymphadenopathy was observed in 5 of 8 patients at laparotomy. Retroperitoneal fibrosis was noted in 2 patients. Obliterative phlebitis of the pancreatic and peripancreatic veins was observed histologically in all 6 resected specimens. Marked stenosis of the portal vein and encasement of the peripancreatic arteries was observed in 4 and 8 of 14 patients who underwent abdominal angiography, respectively. Diabetes mellitus was diagnosed in 13 patients. All associated extrapancreatic lesions except diabetes mellitus improved after steroid therapy.

Conclusions: Extrapancreatic lesions found to be occasionally associated with autoimmune pancreatitis were stenosis of the bile duct, enlargement of the salivary glands, abdominal or cervical lymphadenopathy, retroperitoneal fibrosis, stenosis of the peripancreatic arteries or portal vein, and diabetes mellitus. It is possible that these lesions are induced by the same inflammatory mechanisms as autoimmune pancreatitis.