Calcified disk herniation of the thoracic spine: clinical and imaging features in two cases and review of the literature.

Thoracic disk herniations are more easily detected, in respect to the past, with the increasing availability of MR scanners. However, in several cases, the time interval between the onset of the symptoms and the diagnosis is still long, due to the variability and non-specificity of the clinical pattern and to the good functional compliance of the spinal cord to slowly progressive compression. We describe two cases of non-traumatic calcified thoracic disk herniation with variable extension in the spinal canal, which were not suspected at the initial diagnostic work-up. In the first case, long-standing but subtle disturbances of gait and lower limb sensitivity were associated with a large calcified central disk herniation, which occupied almost all the spinal canal at the T8-T9 level. The lesion was detected with MR of the thoracolumbar spine and further studied with CT for a better definition of the calcified part and its relationship with the nucleus polposus of the corresponding disk. In the second case, a hyperdense mass was observed in the right lateral recess of the T10-T11 intersomatic space during a CT scan of the abdomen, performed in a patient with clinical suspicion of gallbladder stones. The lesion was further studied with MR scan of the thoracic spine for evaluation of the compression on the spinal cord. The literature review and our cases confirm that non-traumatic thoracic disk herniation is a possibility seldom considered in the clinical evaluation, and that, although MR is certainly the optimal diagnostic modality, in our opinion, in cases of herniated disk calcification, a CT scan remains useful, especially when a surgical approach is planned