A 13-year-old boy was referred to Chosun University Hospital for evaluation of inflammatory back pain. He had previously been healthy but complained of persistent back pain and an unsteady gait commencing several months prior. The pain did not respond to medical treatment and buttock discomfort developed. His motor power was intact and he was able to walk without any assistance. A physical examination revealed pain on percussion of the T4 spinous process, reduced sensation below the T5 level, increased muscle tone, positive ankle clonus, and positive Babinski signs. Computed tomography revealed an aggressive osteolytic lesion at the T4 vertebral body, with posterior extensions (Fig. 1A and 1B). Magnetic resonance imaging (MRI) revealed a relatively well-defined, soap bubble-like mass lesion at the T4 level (Fig. 1C). T2-weighted MRI images showed severe anterior displacement and compression of the spinal cord at the T4 level (Fig. 1D). He underwent emergency decompressive surgery and marginal excision of the tumor via T3-T5 laminectomy. Histopathological examination revealed reactive woven bone, fibroblasts, and osteoclast-like giant cells; these findings were consistent with osteoblastoma (Fig. 2). The thoracic pain and numbness of the lower extremities resolved immediately after surgery. He was transferred to the oncology department to undergo radiotherapy.