Multiple Myeloma
Description
Multiple myeloma is the most common primary
bone cancer. It accounts for 1 percent of all cancers. It occurs in about four out of every 100,000 people in the United
States each year. Multiple myeloma is responsible for the deaths of 10,000 Americans each
year.
This disease generally occurs in older
adults. Fewer than 3 percent of cases occur in people under the age of 40. Multiple myeloma tends to be more common in men
than women. It is twice as common in African Americans as it is in Caucasians.
Multiple myeloma is named for the
"clock face"-appearing cells seen under microscopic examination. They infiltrate virtually
all of a patient's bone marrow. These malignant cells come from changed plasma cells. Plasma cells are white blood cells
that secrete antibodies as part of the immune response. The changed plasma cells produce abnormal amounts of an antibody protein
known as the M protein. No one knows the exact cause or location of the cellular change.
Multiple myeloma is not confined to a specific bone or location within a bone. It tends
to involve the entire skeleton.
Multiple myeloma appears on X-rays as decreased
bone density with a lot of "punched out" holes in the bone. These destructive lesions are not surrounded by the white rim
of bone seen in other types of destructive lesions. A bone scan may show which bones are involved with multiple myeloma. But
often the lesions cannot be seen. If a bone scan is negative, a skeletal survey is typically performed. This consists of X-rays
of many different parts of the skeleton
Physically, patients are pale with diffuse bone tenderness, especially around the sternum
(breastbone) and pelvis (hips). Pathologic fractures (fractures caused by tumors) occur frequently. Thirty percent of patients will have their multiple myeloma first discovered when they develop this kind of fracture.
The spine is the most common location for a pathological fracture. It can also happen in the ribs and pelvis.
Compression of the spinal cord occurs in 10 percent to 15 percent of patients. This
causes pain in the back and legs, and numbness and weakness in the legs. Patients who have high levels of calcium in the blood
may experience nausea, fatigue, confusion, constipation and frequent urination. Patients with anemia may experience fatigue,
weakness and shortness of breath with exercise. In advanced cases, patients typically have recurrent infections and can have
kidney failure.
