Thoracic spinal intradural arachnoid cyst: report of two cases and review of literature.

We report two cases of spinal intradural arachnoid cyst at the thoracic level, presenting with long-standing symptoms of spinal cord compression and MRI findings that were overlooked for sometime initially. Because of the rarity of this disease, and because of the subtle changes on MRI, there was a definite delay in the diagnosis. In this report we emphasize the value of MRI and CT myelography in this disorder, and the need for them to be strongly correlated with the progression of the clinical picture.