[Magnetic resonance imaging of rheumatoid pannus in cranio-vertebral synovial joints--report of an operated case].

MRI imaging can provide useful informations as to the status of the brain stem and spinal cord in patients with rheumatoid cervical spine disease. Especially MRI made it possible to visualize the soft tissue mass in the cranio-vertebral joints. However, as far as we know, there is no report describing the pathology of the soft tissue mass diagnosed by MRI. We would like to report an operated case of RA, showing that the soft tissue mass was verified as the so-called rheumatoid pannus in the field of pathology. A 67-year-old woman was admitted to our hospital because of tetraparesis and anterior limitation of neck movements. She had been suffering from rheumatoid arthritis for 17 years. On admission, her consciousness was alert. Cranial nerves were normal except for swallowing disturbance, hoarseness, weakness of neck and tongue muscles. Muscle weakness with atrophy was observed on both upper and lower extremities. Pain and touch sensations were involved below the C3 spinal levels. Laboratory examination showed mild degree of anemia, positive RA test and 40 times value of antinuclear antibody. Brain CT and cerebro-spinal fluid were normal. X-ray of cranio-vertebral joints showed erosive and sclerotic changes of the atlas and odontoid process. Metrizamide CT myelography revealed that C1 spinal cord or medulla was compressed and flattened. A soft tissue mass surrounding the odontoid process was revealed by MRI with Toshiba 0.15 tesla apparatus, showing low signal intensity on T1 image, and low and partially high signal intensity in T2 image. The first operation was done with laminectomy and posterior fusion of occipital bone and C2 spinal process.(ABSTRACT TRUNCATED AT 250 WORDS)