Intrathecal rituximab in immunoglobulin G4-hypertrophic pachymeningitis.

We describe the case of a 69-year-old man who presented with symptoms of headache and severe vision loss due to G4 immunoglobulin (IgG4) hypertrophic pachymeningitis (HP). The patient was initially responsive to corticotherapy, but vision loss progressed when steroid therapy was first tapered. No improvement was noticed with intravenous rituximab. The patient showed clinical and radiological improvement after intrathecal rituximab, which can be an efficacious alternative treatment option.