Immunoglobulin G4-Related Hypertrophic Pachymeningitis Mimicking Chiari Malformation

Dear Editor, Immunoglobulin G4-related disease (IgG4-RD) is a recently recognized clinical entity characterized by elevated serum IgG4 and infiltration of IgG4-positive plasma cells leading to organ swelling or sclerosis.1 IgG4-RD may affect various organs, more commonly the orbit or pituitary gland than the nervous system. However, due to increasing reports on meningeal inflammation associated with elevated serum IgG4, IgG4-related...