Hemorrhagic Synovial Cyst Associated with Rheumatoid Atlantoaxial Subluxation
A 72-year-old woman presented with sudden severe headache in her left occipital area with dyspnea. The patient was alert and the function of cranial nerves was intact. Motor power and sensory were symmetric in all extremities. The dyspnea was aggravated on supine position. It was relieved on flexed head position. She had rheumatoid arthritis for 14-year, which was clinically and serologically proven. A laboratory examination of the patient's blood revealed no remarkable abnormality indicative of inflammation, but high-titer of rheumatoid factor (95.9 IU/mL). Seven months ago before visiting to our department, she checked brain MRI due to sudden attack of severe headache on left occipital area, which revealed non-specific lesion except rheumatoid pannus with small prevertebral cyst of C1-2 junction ().\nOn admission, there was a large hemorrhagic cystic mass around prevertebral space of the atlanto-axial joint on the left side, obstructing the nasopharyngeal cavity on cervical MRI (). The cystic mass was connected to atlanto-axial joint capsule on axial view of computed tomography (CT). Multiple bony erosion, rheumatoid atlanto-axial instability including left tilted C1-2 subluxation and cranial settling were demonstrated. And there were loss of lordosis and retrolisthesis in C 3-4, 4-5 ().\nIn the first operation stage, considering patient's dyspnea, aspiration of the cystic lesion was performed via transoral approach with otolaryngology surgeon () and airway obstruction was relieved. The volume of aspirated cystic fluid was about 5 cc. The color of specimen was xanthochromic, which suggested old hemorrhage. After 0.5 cm-sized mucosal incision on left side oropharyngeal wall, residual material of the cyst was squeezed by forceps and removed by suction tools.\nIn the second operation stage, there were rheumatoid atlanto-axial instability and retrolisthesis in C 3-4, 4-5, so it was followed by posterior occipito-cervical fusion that connected from occiput to C5, using vertex screw & rod system and iliac bone graft (). All the procedure was successfully done.\nThe patient was tolerable on her postoperative course and showed good respiration and relieved headache.