Unusual presentation of osteoblastoma as vertebra plana-a case report and review of literature.

BACKGROUND: Osteoblastoma is rare and accounts for 3% of all benign tumors and 1% of all bone tumors. The spine is the most common site of occurrence, constituting 32% to 45% of all osteoblastomas. It has a strong predilection for the posterior elements, most often occurring in the lumbar spine.

METHOD: In this case report, we describe an unusual presentation of spinal osteoblastoma presenting as thoracic T9 vertebra plana in a 20-year-old female. She presented with discomfort over the midback with unsteadiness of gait. The patient underwent detailed investigations including computed tomography (CT), magnetic resonance imaging, and CT-guided biopsy. To our knowledge, this is the first case report of vertebra plana due to spinal osteoblastoma in the English literature.

RESULT: The patient successfully underwent posterior decompression of T9 with laminectomy followed by minimally invasive surgery posterior instrumentation from T7 to T11. Histopathology of the intraoperative specimen was consistent with osteoblastoma. The patient had an uneventful postoperative recovery and no evidence of tumor recurrence could be demonstrated on positron emission tomography scan at 15 months' follow-up.

CONCLUSION: In conclusion, the differential diagnosis for vertebra plana is extensive and we add spinal osteoblastoma as another etiology to the existing list. Diagnosis and treatment of vertebra plana involve multimodality radiological imaging, and careful histological and surgical evaluation to identify the underlying etiology.