Autoimmune Pancreatitis and Ulcerative Rectocolitis in an Adolescent.

Autoimmune pancreatitis (AIP) is rare in teenagers and difficult to diagnose. There are no clear and established diagnostic criteria in the pediatric population to distinguish subtype 1 and subtype 2. Here, we report the case of a 16-year-old white French teenager admitted to the pediatric emergency service with more than 1 year's history of pain originating from the epigastric and the right hypochondriac regions, with bloody diarrhea. After exclusion of pancreatic cancer and other common causes of acute pancreatitis, the diagnosis of AIP was suspected. Biological analyses revealed acute pancreatitis with severe cholestasis and an elevated level of serum immunoglobulin G4. Magnetic resonance cholangiography revealed a voluminous pancreas presenting a typical "sausage-like" aspect. Anatomopathological analyses of the liver biopsy specimen revealed a biliary obstruction due to pancreatic involvement without the typical aspect of chronic destructive cholangitis. Corticotherapy and immunosuppressive treatment proved effective after 1 week of treatment. Without a pancreatic biopsy specimen, the distinction between AIP type 1 and 2 could not be made clearly in this case. The succession of clinical observations could allow clinicians to recognize, treat, and manage AIP in children.