Meningioangiomatosis. A comprehensive analysis of clinical and laboratory features.

Meningioangiomatosis (MA) is a rare, benign, focal lesion of the leptomeninges and underlying cerebral cortex characterized by leptomeningeal and meningovascular proliferation. It may occur sporadically or in association with neurofibromatosis type 2. Previous reports have emphasized histological and imaging features. Data on the management of these patients are sparse, and electrophysiological features of MA lesions have not been published. We assessed the clinical, electrophysiological, histopathological and imaging features as well as the surgical outcome in MA, and compared MA with and without neurofibromatosis. Seven patients with MA at our centre were investigated and their outcome was assessed. A review of the literature is included. MA exhibits a wide range of clinical, imaging, histopathological and electrophysiological features, making the diagnosis difficult. Sporadic MA cases are not associated with neurofibromatosis and the two disorders are genetically distinct. Medically refractory, localization-related epilepsy is the commonest presentation in sporadic cases, but atypical presentations also occur. Unlike sporadic cases, MA with neurofibromatosis is often found incidentally, does not produce seizures, occurs less frequently (ratio of 1:4), and is multifocal. MRI findings in MA correspond to the histological picture. However, the appearance on imaging is non-specific and may suggest cystic atrophy, angioma and tumours. Several abnormalities have been found in close proximity to MA lesions, i.e. meningioma, oligodendroglioma, arteriovenous malformation, encephalocoel and orbital erosion. In spite of histopathological diversity, MA lesions are either predominantly cellular or vascular. Immunohistochemical results are inconsistent among cases, add little to the diagnosis, and do not support a meningeal origin. Electrocorticographic recordings from the surface and within MA lesions revealed a spectrum of electrophysiological expressions. Intrinsic epileptogenicity of MA lesions was documented in some cases. Epileptogenicity was confined to the perilesional cortex in some patients and it was complex (extralesional, multifocal, generalized) in others. Only 43% of our patients became seizure-free postoperatively compared with 68% previously reported, and >70% of our patients and those in the literature continued to require antiepileptic drugs. This is in keeping with the diverse electrophysiology of MA and suggests a less optimistic postoperative outcome than previously recognized.