Multiple myeloma is a malignant tumor of plasma cells, is a common malignant bone tumor that usually develops in middle age. It is a disorder affecting the entire bone marrow, occurring at multiple sites throughout the skeleton, but may present as a single bone lesion referred to as a plasmacytoma. Any bone can be involved but the spine, ribs, skull, pelvis and proximal long bones are the most common sites. Patients complain of pain in their bones with history of fever, fatigue, weight loss and anemia. X-rays may show a fracture, widespread osteoporosis or small puncture holes in the skeleton which can turn into large areas with thinning of the cortex. Skeletal surveys (plain x-rays of many bones) are done since bone scans may not always show all the tumor site.
Patients with myeloma often do not need a biopsy, but if done, the tissue contains sheets of plasma cells. Blood tests are very helpful to establish the diagnosis. Ninety percent of patients have anemia and a high sedimentation rate. Calcium levels may be elevated in patients with extensive bony disease. The blood test immunoelectrophoresis (IEP), which profiles the immunoglobins, demonstrates an abnormal 'g component' (myeloma protein) in ninely percent of patients. Immunoelectrophoresis studies on the urine is positive in over sixty percent of patients. Diagnosis is confirmed by doing a bone marrow biopsy. Normal bone marrow contains only a small amount of plasma cells. Thus, over eight percent of plasma cells is suspicious for myeloma and over twenty percent confirms diagnosis.
Treatment includes radiation because myelomas respond very well to the therapy and the pain caused by these lesions is relieved. Fractured or weakened areas of bone are treated surgically with internal fixation (metal hardware such as pins, rods, plates, screws and possible cement or bone grafting). New forms of chemotherapy and bone marrow transplantation are also being used.