Autoimmune Pancreatitis in Children: Characteristic Features, Diagnosis, and Management

Abstract

Objectives: Autoimmune pancreatitis (AIP) is an increasingly recognized disease entity, but data in children are limited. AIP presentation and outcome in children might differ from the adult experience. We aim to determine the characteristic features of AIP in children.

Methods: Data about clinical symptoms, imaging, histology, and treatment were collected using two sources: (i) a systematic literature search and (ii) the INSPPIRE database, the largest international multicenter study of pancreatitis in children and the Cliniques Universitaires St-Luc (CUSL) registry.

Results: We identified 48 AIP cases: 30 from literature review, 14 from INSPPIRE, and 4 from CUSL. The median age at diagnosis was 13 years (range 2-17 years). Abdominal pain (43/47, 91%) and/or obstructive jaundice (20/47, 42%) were the most common symptoms at diagnosis. Elevated serum IgG4 levels were only observed in 9/40 (22%) children. Cross-sectional imaging studies were abnormal in all children including hypointense global or focal gland enlargement (39/47, 83%), main pancreatic duct irregularity (30/47, 64%), and common bile duct stricture (26/47, 55%). A combination of lymphoplasmacytic inflammation, pancreatic fibrosis, and ductal granulocyte infiltration were the main histological findings (18/25, 72%). Children with AIP had a prompt clinical response to steroids. Complications of AIP included failure of exocrine (4/25, 16%) and endocrine (3/27, 11%) pancreas function.

Conclusions: Pediatric AIP has a distinct presentation with features similar to type 2 AIP in adults. This comprehensive report on the largest group of children with AIP to date is expected to help with the diagnosis and management of this disease and pave the way for future research studies.

Figure 1

Imaging features of autoimmune pancreatitis in children. (a) Mass lesion in the pancreatic head as shown by endoscopic ultrasound (arrows). (b) Magnetic resonance cholangiopancreatography (MRCP) T2-weighted three-dimensional (3D) cholangiogram reconstruction showing an irregular main pancreatic duct (MPD) in the pancreas tail, and no visible pancreas duct in the head. The common bile duct (CBD) is tapered in its proximal part by a pancreatic head mass (arrow). (c) MRCP T2-weighted HASTE (half-Fourier acquisition single-shot turbo spin-echo) coronal section showing a bulky pancreas (dashed contour). The MPD (arrow) and the distal CBD (arrow) are tapered by the enlarged pancreas head. (d) MRCP T2-weighted HASTE transversal section evidencing an abnormal capsule-like rim hypointense rehearsal in the pancreas periphery (arrow).

Figure 2

Pancreas histopathology in pediatric autoimmune pancreatitis (AIP). Representative histopathologic features on pancreas core biopsies in children with autoimmune pancreatitis (hematoxylin and eosin (H&E) staining). (a) Dense lymphoplasmacytic infiltration of the major papilla (original magnification ×20). (b) Negative IgG4 staining of the plasma cells (original magnification ×20). (c) Granulocytic epithelial lesion (arrow) and focal epithelial duct destruction (dashed arrow). The chorion is infiltrated by lymphoplasmatic cells (original magnification ×20). (d) Storiform fibrosis (original magnification ×40).