Optic nerve sheath meningiomas in patients with neurofibromatosis type 2
To determine the prevalence of optic nerve sheath meningiomas (ONSMs) in patients with neurofibromatosis type 2 (NF2). An observational retrospective case series of 30 consecutive patients with NF2 referred to an academic ophthalmology unit from November 1, 1991, through August 31, 2003. Twenty-six patients were followed up for a mean of 93 months (range, 3-150 months). One individual was lost to follow-up, and 3 had been referred recently. Diagnosis of ONSM was made based on typical neuroradiologic and clinical features in 7 patients and on histologic criteria in 1. Eight of 30 patients harbored unilateral (n = 6) or bilateral (n = 2) ONSMs. Six ONSMs were diagnosed at initial examination, and 4 during follow-up. There is a strong association between ONSMs and NF2 that parallels the well-known association of optic nerve gliomas with NF1. Physicians should be aware of the possibility that patients with ONSMs may also have NF2.