Intraspinal extradural ganglion cyst.

Occurrence of ganglion cysts in the spine is extremely rare. Common symptoms include intermittent lumbar pain and pain at night. Neurological examination to distinguish from other etiologies of radicular pain may be difficult. The L4-L5 level is the most common sight of occurrence. Radiographically, degenerative changes, particularly spondylolisthesis, are a common finding. MRI appearance of the cysts is variable, according to the composition of the cyst. A ganglion cyst should be considered in the differential of radicular pain in the presence of degenerative changes of the lumbar spine.