Primary optic nerve sheath meningioma in children.

Primary optic nerve sheath meningioma represents a proliferation of meningothelial cap cells of the arachnoid villi within the optic nerve sheath. Patients younger than 20 years of age make up less than 5% of all cases of pediatric primary optic nerve meningiomas. Histopathologically, the most common subtypes in children are transitional (54%) and meningotheliomatous (38%). This tumor has been called aggressive in the pediatric population, with surgical excision recommended. However, the tumor may spread intraorbitally, intracranially, or intraocularly after subtotal surgical resection. Recent studies examined the use of fractionated, stereotactic radiation in children with this tumor; however, follow-up is limited. Neurofibromatosis type 2 is concomitantly diagnosed in 28% of patients with pediatric primary optic nerve sheath meningioma. There have been no known deaths attributed primarily to this tumor.