Unusual imaging findings in association with spinal osteoblastoma.

This paper describes four patients with spinal osteoblastoma that had unusual imaging features. Two cases arose in the cervical spine and two in the thoracic spine. Three tumours were associated with diffuse sclerosis of the vertebral body (an 'ivory vertebra'). All of these lesions either arose in the vertebral body or extended into the body from the adjacent pedicle. Reactive sclerosis at multiple levels was seen in three cases (one involving adjacent vertebral bodies, two involving adjacent pedicles or laminae and one involving multiple ribs). Osteophyte formation was identified bridging the disc space on the concave side of a scoliosis in two cases. Another case had an unusual scintigraphic appearance with an area of linear activity adjacent to the tumour. The finding of an 'ivory vertebra' in a child or young adult should raise the possibility of osteoblastoma involving the vertebral body, especially if there is an associated scoliosis.