Background Context. Computed tomography- (CT-) guided fine-needle aspiration biopsy of the vertebral body is an important tool in the diagnostic evaluation of vertebral osteomyelitis. The procedure is considered simple to perform and it is considered a safe procedure with few complications. Purpose. The purpose of this study was to describe an unusual complication due to a CT-guided fine-needle aspiration biopsy of the vertebral body of L3, to better understand the relationship between surgical procedure and complication, and to reflect on how to avoid it. Study Design/Setting. Case report and literature review. Methods. The medical records, laboratory findings, and radiographic imaging studies of an 11-year-old boy, with an unusual complication due to a CT-guided fine-needle aspiration biopsy of the vertebral body of L3, were reviewed. Results. We report a case of vertebral osteomyelitis of L3 caused by methicillin-sensitive Staphylococcus aureus (MSSA). Following a computed tomography-guided aspiration biopsy of the vertebral body of L3, vertebral osteomyelitis rapidly progressed into the vertebral body of L4 as well as the L3-L4 disk. Conclusions. Based on the present case, one should consider that a CT-guided fine-needle aspiration biopsy of the vertebral body may be complicated by a progression of a vertebral osteomyelitis into both the intervertebral disk and also the adjacent vertebral body.