Intradural herniation of thoracic disc: CT metrizamide myelography.

A case of intradural herniation of a thoracic (T12-L1) intervertebral disc is reported. On metrizamide myelography, this lesion resembled an intradural extramedullary tumor with an extradural component. A computed tomographic (CT) scan taken immediately after the myelogram, showed gas in the spinal canal and in the intervertebral disc. In addition, it showed a high-density mass located in the ventral epidural space and also intradurally. The density of this soft-tissue mass was identical to that of the intervertebral disc. CT provided very important information regarding the precise location and probable etiology of the lesion, and the success of surgery.