Huge arachnoid cyst in the posterior fossa: controversial discussion for selection of the surgical approach.

CASE REPORT: We report a case of a huge posterior fossa arachnoid cyst with hydrocephalus. This 15-month-old girl presented with macrocrania and psychomotor retardation. Magnetic resonance (MR) imaging demonstrated ventriculomegaly and a huge cystic lesion in the posterior fossa. A membranectomy was performed microscopically and the patient had a good postoperative course.

OUTCOME: Magnetic resonance imaging 1 year after the operation revealed adequate reduction in the size of the ventricle and cyst. Progressive macrocrania discontinued and normal development was obtained.