Cervical myelopathy attributable to pseudogout. Case report with radiologic, histologic, and crystallographic observations.

A 77-year-old woman complained of numbness in her hands and feet, progressive unsteadiness, weakness, and loss of proprioception of six months' duration. A myelogram revealed stenosis of the spinal canal at the levels of C2-3, T6-7, L2-3, and L3-4. On computerized tomography scan, a large dorsal, epidural, soft tissue mass and focal calcification of the ligamentum flavum were seen at C3. Laboratory studies ruled out gout, collagen disease, vitamin B12 deficiency, syphilis, parathyroid, and thyroid disease. At decompressive laminectomy, a nodular mass in the ligamentum flavum (C2-4) was found and removed. Three months after operation, the neurologic symptoms had improved. Histologic examination of the elastic ligament revealed deposits of birefringent crystals, which were identified by X-ray diffraction as calcium pyrophosphate dihydrate (CCPD). Only about six cases of myelopathy attributable to deposits of CPPD appear to have been previously reported.