Arachnoid Cysts in Childhood

Arachnoid cysts are congenital cystic intracranial mass lesions. With the widespread availability of CT and MRI, they are being diagnosed with increasing frequency. Cysts most commonly expand the sylvian fissure in the middle cranial fossa. Less common cyst sites include suprasellar, hemispheric, and retrocerebellar. The cyst’s relationship with adjacent spinal fluid cisterns and the cerebral hemispheres is best defined by MRI. The majority of cysts are managed nonoperatively. Treatment is recommended when there is severe headache, cyst expansion, or increasing bone deformity. Surgical techniques include placement of a cyst shunt or fenestration of the cyst into the adjacent cisterns or ventricle by open craniotomy or minimally invasive endoscopy. This chapter discusses the natural history of cysts, imaging, and surgical management.