Relapsing autoimmune pancreatitis in a 14-year-old girl.

We present a case of acute pancreatitis in a 14-year-old girl which fulfilled the diagnostic criteria of autoimmune pancreatitis (AIP) and responded to corticosteroid therapy. Imaging studies revealed that the main pancreatic duct was narrow in the head of the pancreas but had been dilated in the body at an earlier stage. The pancreatitis recurred twice when the prednisolone dose was reduced to 10 mg or less but responded each time to an increased dose and has been kept under control with low-dose prednisolone therapy for 3 years since onset. Repeated magnetic resonance cholangiopancreatography during steroid therapy revealed an improvement of the narrowing of the main pancreatic duct in the head and dilation of the duct in the body. AIP in younger patients has distinct clinical features, such as presentation with epigastralgia, back pain without jaundice, and elevated serum amylase levels. The serum level of IgG4 is rarely increased in young patients, indicating a different disease mechanism than for cases in elderly patients. Given the excellent response of this condition to steroid therapy, AIP should be considered even in young children and adolescents when the diagnosis of idiopathic pancreatitis is suggested.