Synovial cyst of the cervical spine: case report and review of the literature.

A 42-year-old woman was in good health until 2 years before admission. when she began to have right-sided neck pain radiating to the right shoulder. This progressed in severity for 18 months. at which time she began having episodes of spontaneous torticollis accompanied by muscle spasms in her neck and right shoulder. In addition. she experienced infrequent episodes of tingling in her right arm. especially when her head was tumed to the left. against the spastic muscles. There were no complaints of motor problems in the extremities. and no history of trauma. On physical examination. the patient's head was turned to the right. with contraction of the sternocleidomastoid muscle and elevation of the right shoulder. The cranial nerves were intact. and there were no sensory or motor abnormalities. Laboratory studies were normal. including sedimentation rate. rheumatoid factor. and antinuclear antibody. Clinical diagnosis was neurogenic torticollis. Radiographs of the cervical spine revealed grade-I spondylolisthesis of C4 on C5. with mild disk space narrowing. There was a hypertrophic spur seen on the posterior aspect of the superior end plate of C5. and slight irregularity of the superior aspect of the C5 facet (Fig. 1). Pleuridirectional tomography disclosed erosion of the inferior and superior facet margins on the right at C4-C5 (Figs. 2 and 3). The margins were slightly irregular. with bone erosion. and were accompanied by mild eburnation of the joint surface. The joint space itself appeared widened. probably due to effusion. CT with first-generation scanners . both with and without contrast. again demonstrated the facet erosion with no soft-tissue mass seen in the periarticular area. Myelography was not performed. At surgery. a soft-tissue mass was seen protruding between the laminae on the right at C4C5. Partial laminectomy of the inferior aspect of the C4 lamina revealed a cystic mass in the region of the facet joint itself. causing widening of the jOint space. The mass was easily dissected free of the C5 nerve root. which had been compressed by the cyst. Clear fluid was obtained from the cyst. Histologic examination revealed fibrous tissue walls with a lining of reactive synovial cells (Fig . 4).