Sclerotic multiple myeloma with an unusual sunburst periosteal reaction occurring in the sternum.

Multiple myeloma is a disseminated neoplastic monoclonal gammopathy that usually affects the skull, clavicle, rib, pelvis, spinal column, and proximal portions of the humerus and femur. The initial manifestation of multiple myeloma in the sternum is rare. The classic radiological presentations of multiple myeloma are multiple "punched-out" areas of bone destruction, expansile lytic lesions, and generalized osteoporosis. Primary sclerotic presentation is rare and occurs in only 3 % of cases. A sclerotic multiple myeloma with a sunburst periosteal reaction occurring in the sternum has not been reported in the English literature. We report a case of sclerotic multiple myeloma of a 49-year-old woman. In the sternum, the lesion displayed extensive sclerosis mixed with mottled lytic areas with a sunburst periosteal reaction occurring in the periphery, which radiologically mimicked an osteosarcoma. Multiple focal areas of sclerosis were also found in the right clavicle, pelvis, multiple ribs, and vertebrae.