Meningioangiomatosis. A clinicopathologic study including MIB1 immunoreactivity.

OBJECTIVE: To examine the etiology of and clinicopathologic findings associated with meningioangiomatosis and to evaluate MIB1 immunoreactivity (marker of cell proliferation) in this lesion.
DESIGN: Retrospective surgical pathology series of three patients.
SETTING: Tertiary referral center with a high volume of epilepsy surgery. PATIENTS: Individuals with meningioangiomatosis who underwent surgical resection of the lesion.
RESULTS: Three patients aged 11, 14, and 32 years (two females, one male) comprise the study. All patients presented with a history of intractable seizures (2, 3, and 30 years duration). None of the patients had von Recklinghausen's disease. All three patients underwent gross total resection of the lesion, and postoperative seizure-free intervals range from 7 to 15 months. Histologically, the lesion is characterized by a proliferation of blood vessels and meningothelial cells arranged around vessels in the meninges, cortex, and underlying white matter. Psammoma body formation or dystrophic mineralization and gliosis of the intervening parenchyma was observed in all three cases. Bodian stains failed to demonstrate neurofibrillary tangles within intervening parenchymal neurons. Focal epithelial membrane antigen positivity was observed in two lesions and was absent in one. MIB1 staining was observed in two lesions (MIB1 index = 0.8 and 0.6) within the meningothelial cell nuclei and was absent in one case.
CONCLUSIONS: Meningioangiomatosis is a rare malformative or hamartomatous lesion of the central nervous system characterized by a proliferation of vessels and perivascular cuffs of meningothelial cells. Absent MIB1 immunoreactivity or low MIB1 indices in the lesion support the clinical impression of a slow-growing lesion and further support a malformative or hamartomatous etiology.