summary Pathologic Scoliosis is a form of scoliosis resulting from a benign bone tumor most commonly located in the posterior elements of the spine. Diagnosis is made with full-length standing spine radiographs to determine the severity of the curve. A CT scan is useful to assess for the size and location of the underlying lesion. Treatment is observation and NSAIDs for small and minimally symptomatic curves. Surgical resection of the lesion is indicated for painful, progressive scoliosis. Epidemiology Demographics can occur in all age groups Etiology Causes osteoid osteomas occur in the apex of the concavity of the curve curves are typically rigid can occur in the vertebral body or posterior elements demonstrate same histology as osteoid osteomas in the peripheral skeleton osteoblastomas larger lesion than osteoid osteoma pain is usually less severe than osteoid osteoma Mechanism scoliosis is thought to develop in response to painful paraspinal muscle spasms Presentation Symptoms back pain most commonly at night pain relieved by anti-inflammatories less relief reported with osteoblastomas Physical exam posterior trunk curvature of the spine usually mild neurological exam may have neurological deficits with osteoblastoma findings dependent on level of lesion Imaging Radiographs AP/Lateral of spine can determine level and severity of curvature findings lesion is defined by cortical thickening with radiolucent nidus osteoid osteoma is less than 2 cm in diameter by definition osteoblastoma is greater than 2 cm CT scan fine cut best for outlining lesion and determining treatment plan MRI good for showing proximity to neurovascular structures may only show soft tissue edema and not the nidus Bone scan markedly increased uptake in area of lesion Treatment Non-operative NSAIDs, observation indications minimal curve outcomes may take up to 36 months to resolve osteoblatomas usually do not respond to NSAIDS Operative en bloc resection of lesion indications painful, progressive scoliosis outcomes resolution of curve if removed with 15-18 months of onset of curve in child less than 11 years old radiofrequency ablation of lesion indications usually not an option due to proximity of neurological structures of spine case by case basis based on 3D studies (CT, MRI) Prognosis Outcomes good with treatment most cases of scoliosis due to osteoid osteoma will resolve after resection of tumor if performed within 15-18 months of onset of curvature child is less than 11 years of age