Non-communicating extradural arachnoid cyst of dorsal spine.

Extradural arachnoid cyst in the spine is an uncommon cause of spinal cord compression in the paediatric population. Most reported cysts have communication with the intrathecal subarachnoid space through a small defect in the dura. The reported child had spinal cord compression caused by a large spinal extradural arachnoid cyst in dorsal spine that did not communicate with the intradural subarachnoid space. Surgical excision of cyst was done with recovery of neurological deficit postoperatively.