‘Plasmacytoma’ is one of the plasma cell neoplasms locally infiltrating bones or spreading to extramedullary sites from the bones. The new World Health Organization (WHO) criteria define solitary plasmacytoma of bone (SPB) as ‘a localized bone tumor consisting of plasma cells identical to those seen in plasma cell myeloma, which appears as a solitary lytic lesion on radiological examination. Considerable debate exists regarding the relationship of SPB and EMP to multiple myeloma (MM). Most authors agree that EMP has a different natural history from both SPB and MM and believe that SPB is simply an early presentation of MM whereas others consider that SPB is a clinical entity distinct from MM. Multiple myeloma is the most common primary malignancy of bone, representing 43% of primary malignancies of bone in the Mayo Clinic series. Bone pain is the most common complaint for patients with SPB as with multiple myeloma.