Refractory IgG4-related intracranial hypertrophic pachymeningitis responded to rituximab

Immunoglobulin G4-related disease (IgG4-RD) is a novel clinical entity characterized by elevated serum IgG4 levels and histopathologic features of storiform fibrosis, obliterative phlebitis, tissue eosinophilia, and infiltration of IgG4-positive plasma cells. Although it can involve almost any organ, IgG4-RD rarely involves the nervous system. The principal neurologic manifestations include hypophysitis and hypertrophic pachymeningitis (HP). In some patients, previously known idiopathic HP may in fact be IgG4-related. IgG4-related CNS disease often resolves with surgery, steroids, and immunomodulators, considered standard treatment. We report a case with IgG4related HP refractory to steroids and multiple immunomodulators. We share our diagnostic and treatment approach that may change the concepts of IgG4-related HP.