This case report details the case of a 57-year-old male who initially manifested low back pain radiating from the lumbar region to the left leg. Progressive symptoms included paresthesia on the plantar surfaces of both feet and gait instability attributed to weakness in the pelvic limbs. Computed tomography imaging revealed osteolytic lesions in the T9, T10, and T11 vertebral bodies, resulting in compression of the spinal cord. Subsequent contrast-enhanced magnetic resonance imaging validated these findings, confirming the presence of an extradural tumor. In accordance with the Spinal Instability Neoplastic Score (SINS), the case was categorized as indicative of potential spinal instability. Consequently, a surgical intervention was performed to excise the lesion. Thus, the role of SINS played a pivotal role in guiding the decision-making process for the chosen treatment modality.