Multiple myeloma: primary bone tumor with systemic manifestations.

Multiple myeloma is a plasma cell dyscrasia that frequently involves the bone marrow of the spine. These tumors are typically chemosensitive and radiation sensitive. Multiple myeloma promotes osteoclast activation and osteoblast inhibition, resulting in osteolysis of the vertebral bodies and subsequent compression fractures. Rarely is open surgery for decompression and instrumentation indicated. The presence of diffuse osteoporosis in patients with multiple myeloma increases the probability of failed fixation in this population.