Multifocal autoimmune pancreatitis complicated by pancreatic insufficiency and segmental portal hypertension: A case report and review of the literature

Autoimmune pancreatitis is an increasingly recognized variant of chronic pancreatitis, classified into 2 subtypes by the international consensus diagnostic criteria: type 1, associated with IgG4 (Immunoglobulin G4)-related disease, and type 2, a pancreas-specific disorder often linked to inflammatory bowel disease. The diagnosis is based on histology, imaging of pancreatic parenchyma/ducts, serology (serum IgG4 levels), other organ involvement or extrapancreatic manifestations, and response to the steroid treatment. Cross-sectional imaging, including computed tomography (CT) and magnetic resonance imaging (MRI), is crucial for diagnosing both autoimmune pancreatitis subtypes, which exhibit a wide range of imaging patterns, the most commonly described being diffuse pancreatic enlargement with a fibrous pericapsular rim. Multifocal presentations of autoimmune pancreatitis are less common and often more challenging to diagnose because of an important overlap with pancreatic malignancies. Autoimmune pancreatitis is commonly described as a cause of exocrine pancreatic insufficiency; it can also be associated with severe compressive complications, such as biliary dilation and portal hypertension. We report a rare case of a multifocal pattern of type 2 autoimmune pancreatitis, revealed by pancreatic insufficiency, imaged with both CT and MRI, which initially raised suspicion of malignant pancreatic masses, and which was complicated by segmental portal hypertension.