Idiopathic hypertrophic cranial pachymeningitis.

We evaluated 3 patients with biopsy-proven hypertrophic cranial pachymeningitis apparently unrelated to any systemic disease. Each patient had chronic headache, cranial neuropathy, an elevated ESR, and a mild CSF pleocytosis. Neuro-ophthalmic findings included bilateral sixth nerve palsies in two patients and the third had bilateral optic neuropathies. MR imaging revealed thickened dura that enhanced with Gd-DTPA administration. Histologic examination showed thickened, fibrotic dura with a sterile, chronic, nongranulomatous inflammation. The response to treatment was variable with corticosteroids, immunosuppressive drugs, or radiation. The distinctive MR appearance should help physicians recognize this rarely reported disease.