Summary
Multiple myeloma is a malignant tumor of plasma cells that causes widespread osteolytic bone damage.
Complete Information on this Tumor
Multiple myeloma is a malignant tumor of plasma cells that causes widespread osteolytic bone damage. Multiple myeloma is the most common primary tumor of bone and is found in the spine, skull, ribs, sternum and pelvis but may affect any bone with hematopoietic red marrow. There are chromosomal abnormalities that are associated with MM, such as 14q32 and deletion of chromosome 13, and these findings are more likely to be found in cases with poor outcome. Other diseases, such as solitary plasmacytoma and monoclonal gammopathy are associate with MM. Approximately 10% of patients with these diseases will eventually develop MM.
The presenting symptoms of multiple myeloma are often fatigue and bone pain, but patients may have other symptoms associated with organ failure, such as kidney failure, infection, and anemia. Some patients may have asymptomatic myeloma, where the abnormal cells are present but symptoms and organ damage are not. MM patients may have a normocytic, normochromic anemia secondary to marrow failure and an increased ESR. Hypercalcemia may cause confusion, weakness and lethargy. Other symptoms may include cachexia, spinal cord compression and renal insufficiency. Bacterial infections are common because of a lack of normal immunoglobulin production.
Monoclonal immunoglobulin (Ig G)is found on serum electrophoresis and on urinalysis. Immunoglobulin (Ig) is the protein that is produced by the tumor cells. Light chain subunits of immunoglobulin are called Bence Jones proteins and are present in urine.
Initial tests include a quantitative assay for Ig, kidney function tests, serum calcium, and a beta-2 microglobulin level. Bone marrow biopsy is required to meaure the percentage of plasma cells in the bone marrow. More than 10% plasma cells is a diagnostic feature of MM.
Bone damage is common and can be severe in MM, and a large percentage of patients will develop pathologic fractures. Careful skeletal evaluation and monitoring, as well as close consultation with an orthopedic tumor specialist are recommended. Depletion of bone mineral / calcium levels can lead to severe fracture risk, but can be avoided or minimized with proper care. Bone preservation treatments should be instituted at the earliest possible moment.
Orthopedic surgeons are an essential part of the treatment team in multiple myeloma. The orthopedic surgeon may be required to evaluate a painful bone lesion for possible pathologic fracture risk. The orthopedic surgeon must make the appropriate decision between operative and non-operative treatment modalities. Please see separate sections on this website for guidelines for the evaluation of pathologic fracture risk.
Multiple myeloma patients who are being prepared for stem cell transplant deserve special consideration. Bone lesions in high risk areas may be considered for aggressive surgical treatment. If pathologic fracture occurs during the stem cell transplantation process, long delays in treatment and associated morbidity are more likely to occur.
Orthopedic surgeons may be the first position to encounter the painful bone lesion in patients with undiagnosed multiple myeloma. Prior to surgical stabilization of these lesions, medical stabilization should be accomplished to minimize the potential for surgical complications.
Patients with multiple myeloma have an increased risk of postoperative deep venous thrombosis and should be managed accordingly.
Surgical stabilization of lesions can be accomplished using multiple techniques according to the location and extent of the tumor, the condition and prognosis of the patient, and the surgeons preferences. Since the average survival after diagnosis of patients with multiple myeloma is four years, robust and durable methods of surgical reconstruction should be employed, especially in weight-bearing sites.
Spinal lesions are common, and spinal compression fractures may occur. Percutaneous vertebral plastic techniques have been proven to be effective. Bulky spinal disease and spinal disease where cord compression is present or imminent may be managed with radiation in many cases. Spinal decompression surgery may be required and is effective in improving quality of life and neurologic function.
Radiation therapy is typically used to limit progression of early bone lesions and for palliative pain relief.
Multiple myeloma: diagnosis and orthopaedic implications.
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JAAOS Vol 19 No 7 July, 2011 p 410 - 419
7/15/2011
