Intrathecal IgG4 synthesis in IgG4 related spinal hypertrophic pachymeningitis: a case report.

Immunoglobulin G4 (IgG4) related hypertrophic pachymeningitis of the spinal cord is a rare condition, characterized by infiltration of the spinal meninges with IgG4-producing plasma cells and subsequent hypertrophic fibrosis. Here, we report on a 65-year-old woman with IgG4 associated hypertrophic spinal pachymeningitis, in whom cerebrospinal fluid (CSF) analysis was a decisive diagnostic tool. Not only could we demonstrate an intrathecal IgG4 production, but also IgG4 positive plasma cells in CSF. Following decompressive surgery, diagnosis of IgG4 associated hypertrophic pachymeningitis was confirmed histologically. Surgery and immunosuppressive therapy with rituximab were associated with clinical improvement. This case highlights CSF analyses as diagnostic tool for detection of IgG4 related hypertrophic pachymeningitis.