Ganglion cyst in the ligamentum flavum of the cervical spine causing myelopathy: report of two cases.

BACKGROUND: Ganglion cyst in the ligamentum flavum is commonly found in the lower lumbar region; occurrence in the cervical region is extremely rare. We report two cases of ganglion cyst in the cervical region and the clinical, pathological, and radiological findings. METHODS: The first patient was an 81-year-old man who was admitted to our hospital with gradually progressive gait disturbance and radiating pain in both arms and legs, which was dominant on the left side. The second patient was a 65-year-old man with progressive muscle weakness of the extremities who was admitted with radiating pain in the right arm. In both cases, the cervical spinal cord had been compressed by the cystic mass with degeneration of the ligamentum flavum (the former left, the latter right) at the level of C3-4. RESULTS: The extradural-intraspinal cystic masses, which were revealed by computed tomography (CT) and magnetic resonance imaging (MRI) to be situated antero-laterally to the cervical laminae, were removed surgically without difficulty. After surgery, the symptoms and neurologic signs improved in both cases. CONCLUSIONS: Ganglion cyst in the ligamentum flavum of the cervical spine is a very rare lesion causing radiculo-myelopathy. In both our cases, a correct diagnosis could be established preoperatively based on CT myelogram and MRI findings, and the results of surgery were excellent.