Ventral thoracic spinal cord herniation: a commonly misdiagnosed and treatable cause of myelopathy.

Idiopathic ventral spinal cord herniation is a rare cause of progressive myelopathy that demonstrates unique radiological features. We describe a case of thoracic spinal cord herniation through an anterior dural defect and discuss the characteristic findings on magnetic resonance imaging and computed tomographic myelography. A 36-year-old man presented to our clinic with progressive leg weakness and spasticity in both legs. Magnetic resonance imaging of the thoracic spinal canal demonstrated C-shaped anterior kinking of an atrophied spinal cord and enlarged dorsal subarachnoid space at the T5-T6 level. Computed tomographic myelography showed ventral herniation of the spinal cord and no evidence of an intradural spinal arachnoid cyst. Ventral spinal cord herniation is a commonly misdiagnosed entity. Knowledge of the characteristic imaging appearance of this treatable condition is important for proper diagnosis and treatment.