- Tumoral calcium pyrophosphate dihydrate crystal deposition disease and tumoral calcinosis (TC) are rare non-neoplastic conditions which may cause symptoms of spinal cord compression when they manifest in the perispinal tissues. There is little information available to compare these conditions with each other. We report a case of a patient with such a calcified mass impinging on the spinal cord. A 39-year-old woman on hemodialysis presents with progressive quadriparesis and monoplegia and is found to have a large calcified mass impinging on the spinal cord at the level of C3-4. The mass is excised by an anterior approach with corpectomy and fusion. Pathology was tumoral calcium pyrophosphate dihydrate crystal deposition disease versus TC. Both conditions are very rare in the perispinal tissues with 21 reported cases of tumoral calcium pyrophosphate dihydrate deposition disease and 39 cases of TC. Both cause compressive symptoms depending on the site of occurrence. Tumoral calcium pyrophosphate deposition disease is characterized by smaller, round, masses typically in ligamentous structures which may erode into adjacent bone. Tumoral calcinosis displays larger, lobulated, irregular lesions which do not erode into bone. Either lesion may contain calcium pyrophosphate dihydrate or hydroxyapatite. Treatment is surgical decompression, though lesions may recur.