An Unusual Presentation of Immunoglobulin G4-Related Disease (IgG4-RD) Causing Subglottic Stenosis.

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory condition that is known to involve multiple organs and was first described as an entity in 2003. It is characterized by lesions with a dense lymphoplasmacytic infiltrate, IgG4-positive plasma cells, storiform fibrosis, and frequently elevated serum IgG4 levels. Organs that are commonly involved include the pancreas, biliary tree, salivary glands, periorbital tissues, kidneys, retroperitoneum, lungs, pleura, thyroid, aorta, and lymph nodes.