Teaching NeuroImage: Pachymeningitis and Aortitis as the Initial Presentation of Granulomatosis With Polyangiitis

A 66-year-old man presented with a 1-year history of progressive cognitive decline, gait instability, and hearing loss. MRI of the brain showed extensive pachymeningeal thickening and enhancement with marked occlusion of intracranial dural venous sinuses (Figure 1). Lumbar puncture revealed pleocytosis at 140 cells/mm3 (96% lymphocytes) and elevated protein at 560 mg/dL. Serum syphilis screen, immunoglobulin G4, and proteinase 3 antibody were negative. Myeloperoxidase antibody was borderline positive. Systemic evaluation revealed evidence of aortitis and severe aortic regurgitation (Figure 2A). Dural biopsy was consistent with granulomatosis with polyangiitis (GPA).1 Special stains for microorganisms were negative (Figure 2, B-D). The patient was treated with intravenous methylprednisolone, followed by an oral prednisone taper. Rituximab was initiated.2 He returned in 2 months with near resolution of neurologic symptoms. Pachymeningitis can rarely be the initial manifestation of GPA, leading to cranial nerve impingement and venous outflow obstruction. Tissue biopsy and systemic evaluation are important in making the diagnosis.