Thoracic myelopathy revealing a chronic ossificans arachnoiditis of the thoraco-lumbar spinal cord

We report a case of chronic spinal, ossificans, thoraco-lumbar arachnoiditi s, associated with an arachnoidal cyst at the level of TH7, and revealed by a rapidly progressive thoracic myelopathy. Two years ago, he had presented with a spinal intrathecal haemorrhage of unknown etiology. There was no ev idence of spinal traumatism, arterial hypertension or coagulation disorder. The finding of several small cysts and angiomas in the liver of this patie nt lead us to suspect an associated spinal vascular malformation, not detec ted on the spinal magnetic resonance imaging. A partial neurologic improvem ent was observed after laminectomy and cysto-peritoneal derivation.