Plasma cell myeloma usually presents as destructive lesions involving bones of the axial skeleton. The most commonly involved sites (in the decreasing order of frequency) include vertebral column, ribs, skull, pelvis, femur, proximal humerus, clavicle, and scapula as shown in this graphic. The lesions start in the medullary cavity, erode their way through the cancellous bone, and eventually destroy the cortex, often resulting in pathologic fractures. Plasma cell myeloma is a neoplasm of older individuals. The median age at diagnosis is 68 years (although it is shown as 57 years among the 706 patients treated at the source of this graphic). It does not occur in children and is rare before age 35 years. The vast majority of patients are above 50 years of age. It makes up 10% to 15% of hematopoietic malignancies in the US. It is more commonly seen in males and in African-Americans. Slide courtesy of Piero Picci, M.D., Director, Laboratory of Experimental Oncology, Instituto Ortopedico Rizzoli, Bologna, Italy. Used with permission.