Autoimmune pancreatitis (AIP) is a rare cause of recurrent acute pancreatitis or chronic pancreatitis in middle-aged patients, and is characterised by a marked infiltration of lymphocytes and plasma cells in pancreatic tissue. Diagnosis of focal forms can be difficult as AIP may mimic pancreatic adenocarcinoma. Pediatric cases of AIP are exceptional. We report the case of a 15-year-old girl who had a focal AIP and associated cholangitis, with a very unusual vascularized mass that mimicked a pancreatic endocrine tumor. The diagnosis was obtained by a pancreatic biopsy, thus avoiding surgical resection, and all the clinical, biological and radiological abnormalities resolved after steroid therapy with 6 mo of follow-up.