Lumbar Spine Osteoblastoma with Secondary Aneurysmal Bone Cyst Causing Severe Trunk Imbalance and Radiculopathy: A Case Report

INTRODUCTION: Osteoblastomas are primary bone tumors, rarer than osteoid osteomas, and <10% of these lesions occurs in the spine. Aneurysmal bone cysts (ABCs) are rare, benign lesion of the bone and approximately 8–30% of ABCs arise in the spine, mostly in the thoracic and the lumbar regions. The association between them is quite rare in the general population. CASE REPORT: We report a case of a 14-year-old boy, soccer player, with an osteoblastoma of the left posterior neural arc of L2 and a secondary aneurismal bone cyst compressing the left L2 nerve root, causing severe antalgic scoliosis and back pain with radiculopathy. A complete surgical excision with radicular decompression has been performed, and the histologic examination confirmed the diagnostic hypothesis (osteoblastoma + ABC). At 6 months follow-up, the patient presented a complete resolution of symptoms, but the trunk imbalance was not completely resolved. CONCLUSION: Spine localization of osteoblastoma + ABC is rare and its diagnosis and treatment are often challenging. Complete surgical excision seems to be confirmed as the gold standard of treatment, but the option of instrumented arthrodesis should be carefully evaluated.