Vertebral osteoblastoma: are radiologic structural changes necessary for diagnosis?

A case of osteoblastoma localized at the pedicle of the 10th thoracic vertebra is presented.

The patient complained of nocturnal back pain not relieved by salycilates, a typical symptom of osteoblastoma. Bone scintigraphy showed a lower thoracic focus of increased osteoblastic activity; however, X-rays, computed tomography, and magnetic resonance images (MRI) were within normal limits, showing only obscure changes that were also noted in the rest of the spine. Repeat MRI with contrast revealed a focal enhancement. After pediculectomy, histopathologic examination confirmed the diagnosis of osteoblastoma. Fifteen months postoperatively, the patient is symptom-free.

Our case demonstrates that some cases of osteoblastoma may not have the classical radiological appearance. Although non-contrast computed tomography and T1-weighted MRI are mildly positive in some instances, osteoblastoma is best visualized on MRI with gadolinium. Like any other neoplasm, osteoblastoma should be detected and removed early, before it can cause structural bony changes.