The mean survival of patients with skeletal solitary plasmocytoma is 75% at 5-year follow-up. This highly osteolytic tumor may compromise spinal stability. Radiotherapy is effective in local control of the disease, however, it is not effective in restoring spinal stability. Fracture risk and progressive vertebral collapse persist. For this reason, we must consider the need to establish the probability of progressive vertebral collapse, based on the degree of involvement of the vertebral body at the time of diagnosis. We used parameters described by Taneishi and Kaneda, as well as those of Heller and Boden to predict progressive vertebral collapse. Three cases are presented and their treatment is described.