Extradural arachnoid cyst: case report and literature review

Abstract

Extradural arachnoid cysts (EAC) are a rare entity that may cause spinal cord or radicular nerve compression, usually in young adults. The most common locations are the posterior or posterolateral region of the thoracic spinal canal or the thoracolumbar junction.

The most accepted theory is that they are formed by the protrusion of the arachnoid through a defect in the dura, they progressively increase in size through physiological Valsalva maneuvers performed dailyand then they can become symptomatic by direct neural compression.

Surgery is the treatment of choice for these cases, with complete removal of the cyst and closure of the dural defect. Extradural arachnoid cysts have generally a good prognosis.

This article aims to present a case of an extradural arachnoid cyst in a 13 year old patient with spinal cord compression syndrome (paraparesis with hyperreflexia, clonus and alteration of deep sensitivity in the lower limbs), without previous history of trauma. Dorsal spine magnetic resonance imaging revealed an extradural cystic lesion with significant spinal cord compression similar to the CSF in T2 weighted images. The lesion extended from T6 to T9.