Primary central nervous system vasculitis with prominent leptomeningeal enhancement: a subset with a benign outcome.

Objective: Primary central nervous system vasculitis (PCNSV) is an uncommon condition that affects the brain and spinal cord. This study was undertaken to evaluate the clinical features and outcomes among patients with PCNSV who presented with prominent gadolinium meningeal enhancement on magnetic resonance imaging (MRI).
Methods: Through retrospective review using the Mayo Clinic medical records linkage system, we identified 101 consecutive patients with PCNSV based on brain biopsy or conventional angiography (or both) between January 1, 1983, and December 31, 2003. We evaluated data on demographics, clinical findings, laboratory studies, imaging, biopsy of brain or spinal cord (or both), treatment, and neurologic outcome.
Results: MRIs showed prominent leptomeningeal enhancement in 8 of 101 patients with PCNSV. In 6 of those 8, cerebral angiography or magnetic resonance angiography results were normal, but biopsy of the brain or spinal cord showed vasculitis in all 8. Granulomatous vascular inflammation was found in 6 specimens and was associated in 4 cases with vascular deposits of beta-amyloid peptide. All 8 patients had a prompt response to therapy, with resolution of the MRI meningeal enhancement. Although 3 of the 8 patients had relapses during followup, the overall outcome was favorable. Patients with meningeal enhancement, compared with patients without enhancement, more commonly had substantial abnormalities of cerebrospinal fluid (100% versus 58%; P = 0.02) and amyloid angiopathy (50% versus 12%; P = 0.03).
Conclusion: Prominent gadolinium leptomeningeal enhancement on MRI may point to a distinct subtype of PCNSV with small leptomeningeal artery vasculitis and rapid response to therapy.