Solitary syndesmophyte in odontoid process of a patient with ankylosing spondylitis.

A 22-year-old male patient was admitted to the rheumatology clinic due to neck and back pain with morning stiffness for 12 months. He suffered from right knee and heel pain six months ago. He showed increased levels of high-sensitivity C-reactive protein (2.20 mg/dL, reference range: 0.01-0.3 mg/dL) and erythrocyte sedimentation rate (67 mm/h, reference range: 0-15 mm/h). To evaluate neck and back pain, the physician performed computed tomography (CT) of the whole spine. The CT finding was absence for herniated nucleus pulposus nor neural foramen stenosis. All vertebral corners of whole spine were clear (Figure 1a), except for bony spur at odontoid process of C2 (Figure 1b, white arrow).