Catching a chameleon: IgG4-related systemic disease.

Abstract

IgG4-related systemic disease (IRSD) is a recently described entity with protean manifestations. We describe a patient who developed inflammation and fibrosis in multiple organs over 20 years, sequentially involving his pancreas, bile ducts, gallbladder, submandibular and lacrimal glands, and kidneys. He had an elevated serum IgG4 level. Retrospective analysis of biopsies showed strongly positive tissue immunostaining for IgG4, confirming the diagnosis of IRSD. This case illustrates the natural history of partially treated IRSD and its varied clinical presentations. Early diagnosis and treatment is important, as the condition is highly steroid-responsive.