[Ocular manifestations of arachnoid cysts in children: report of two cases].

Arachnoid cysts are congenital benign intracranial collections of cerebrospinal fluid. Most arachnoid cysts are small and asymptomatic. They are usually located in the temporal fossa. Classically described complications result from compression of adjacent structures and include neurologic involvement, headaches and seizures. There are few cases of arachnoid cysts with ophthalmic manifestations reported in the literature. We describe two pediatric cases of arachnoid cyst with ocular complications. A 12-month-old girl with a history of acquired nystagmus and enlarged head circumference was referred for ophthalmologic examination. An MRI study showed a 7cm×7cm arachnoid cyst in the left temporal fossa. Six months after cystocysternostomy, the nystagmus resolved. A 2-year-old girl with esotropia and severe amblyopia of the left eye was referred for ophthalmologic examination. Optic nerve hypoplasia was detected on left fundus examination. MRI demonstrated a supracellar arachnoid cyst with mass effect on the optic chiasm as well as hydrocephalus. She was referred to neurosurgery for shunt surgery. In the case of clinical signs such as nystagmus, optic nerve hypoplasia, papilledema and oculomotor palsy, an arachnoid cyst may be a probable cause.