Focal-Type Autoimmune Pancreatitis Mimicking Cholangiocarcinoma / 대한내과학회지

ABSTRACT

Autoimmune pancreatitis (AIP) is a rare pancreatic disorder of autoimmune etiology. It has characteristic clinical features, such as pancreatic parenchymal swelling and irregular narrowing of the main pancreatic duct due to plasma cell infiltration. It occurs mostly in Far East Asia. Although it generally involves whole pancreatic parenchyma, some cases demonstrate focal involvement of the pancreas or adjacent organs, which are often mistaken for cancer. We report a case of AIP that was confused with cholangiocarcinoma of the distal common bile duct (CBD). The patient experienced sudden development of jaundice with vague abdominal discomfort. Abdominal computed tomography revealed a well-enhanced lesion, and positron emission tomography showed high standard uptake value at the distal CBD, indicating malignant disease. However, pathological examination by surgical excision indicated focal-type AIP. This is believed to be the first case of focal-type AIP mimicking cholangiocarcinoma.