Giant spinal extradural cyst.

A case of giant extradural cyst in a 13-year-old girl is described. The cyst was formed by the arachnoid membrane which extruded through a wide lumbar dural defect. It extended from the midthoracic region down to the sacral canal. At operation a large portion of the cystic wall was removed, but the dural defect was not repaired. Two spino-peritoneal shunts were left in place to drain both the intradural and the extradural spaces. The treatment has proved successful during the 20 months that the patient has been observed.