South Med J 2002 Oct;95(10):1180-6
Gutrecht JA, Berger JR, Jones RH Jr, Mancall AC.
Department of Neurology, Lahey Clinic Medical Center, Burlington, Mass, USA.
Monofocal acute inflammatory demyelinating (MAID) lesions present as large masses that mimic brain tumors. The natural history and nosologic classification are not well defined.
Five patients with MAID from our files and 4 from the literature are presented. We defined MAID as a mass-like lesion, >4 cm in diameter. Demyelination was pathologically proven in all patients.
Headaches and motor deficits were the most common presenting symptoms. Language problems and motor deficits were the most common findings on physical examination. After a median follow-up of 44 months, none of our 5 patients had multiple sclerosis. In similar cases, additional lesions indicative of multiple sclerosis developed within an average of 8 months.
It may be difficult to distinguish MAID from brain tumor. It may be that MAID represents a unique form of isolated demyelinating disease, or it may represent transition to multiple sclerosis.