Non-communicating extradural arachnoid cyst: a rare case report with review of literature

Extradural arachnoid cysts in the spine are uncommon causes of spinal cord compression in the paediatric population that are thought to arise from congenital defects in the duramater. In most literatures it is describe that such cysts communicating with the intrathecal subarachnoid space through a small defect in the dura. In this case report we describe a case of a child who presented with spinal cord compression caused by a large spinal extradural arachnoid cyst that did not communicate with the intradural subarachnoid space. An 9 year-old girl presented with progressive lower-extremity weakness, myelopathy, and severe gait ataxia. Magnetic resonance imaging of the spine demonstrated a large extradural arachnoid cyst extending from T4 to T9. The patient underwent a thoracic laminectomy for en bloc resection of the spinal extradural arachnoid cyst. Intra-operatively, the dura was intact and there was no evidence of communication into the intradural subarachnoid space. Postoperatively, the patient’s motor strength and ambulation improved immediately, and no subsequent cerebrospinal fluid leak occurred.