I Have an Elderly Patient With Multiple Lesions in the Cervical/Thoracic and Lumbar Spine. Which Laboratory and Imaging Studies Should I Obtain?
At the initial assessment, I would obtain full spinal radiographs as well as a complete skeletal survey to assess other bony lesions that may be present. The presence of multiple lytic lesions in an elderly patient would most commonly suggest either metastatic disease or multiple myeloma. Both disease processes can affect the axial and appendicular skeleton. Early detection and treatment of long bone or hip lesions may prevent a pathological fracture.
The patient’s history, such as cigarette smoking, may point toward a primary tumor. A thorough physical exam of the patient, including examination of the breast (females predominately), prostate (males), and lymphatic system is needed to help detect a primary tumor source. Cancer screening exams, such as mammography and colonoscopy, should also be performed if needed. In addition to this, I would obtain CT scans of the patient’s head, chest, abdomen, and pelvis. This may identify metastatic tumors present within other organ systems such as the liver, lungs, and central nervous system that may help identify a primary tumor site such as the lung, kidneys, large bowel, ovaries, or pancreas.
A standard Technitium-99 (Tc99) radionucleotide bone scan may demonstrate skeletal lesions that are otherwise not visualized on routine radiographs. Bone scans highlight areas of high bone turnover, specifically areas of high osteoblastic function. Most metastatic tumors lead to bone turnover through a paracrine effect on native osteoclasts, which secondarily activate osteoblasts. Multiple myeloma, in contrast, directly causes bony destruction, avoiding the osteoclastic/osteoblastic pathway. A bone scan in multiple myeloma lesions is therefore notoriously “cold” in a large number of patients. Therefore, I do not rely on standard Tc99 bone scans to identify all multiple myeloma lesions. Although modifications of standard bone scans have been demonstrated to identify and track multiple myeloma lesions, they are not widely available.1
I would obtain a magnetic resonance imaging (MRI) scan of the cervical, thoracic, and lumbar spine to evaluate the known lesions as well as to identify lesions that may not be seen on routine imaging or radionucleotide scans.2 Although the MRI will not help with the differential diagnosis, it provides anatomic information as to the size and location of the lesions as well as any neurological compression that may also exist. This is invaluable information when the time comes to decide on the treatment.
Laboratory studies can aid in the diagnosis of both metastatic disease and multiple myeloma. Serum erythrocyte sedimentation rate will be elevated in both diseases. Serum alkaline phosphatase is typically elevated in metastatic disease because of high osteoblastic activity. Again, because of the direct effect of multiple myeloma on bone destruction, alkaline phosphatase is usually not elevated in multiple myeloma. I do not rely heavily on alkaline phosphatase because a number of disease processes can affect serum levels; it is most useful in cases of Paget’s disease.
Serum protein electrophoresis (SPEP) will typically identify a discrete, abnormal band of immunoglobulin (IgA or IgG) in 80 to 90% of patients. Major criteria for diagnosis include a monoclonal globulin spike larger than 3.5 g (for IgG) or larger than 2.0 g (for IgA) per 100 ml. In addition, urine protein electrophoresis (UPEP) can identify a monoclonal spike in 50% of patients, especially those with an IgG myeloma.2 Evidence of anemia, thrombocytopenia, renal failure, or hypercalcemia points to multiple myeloma. The anemia is usually a normocytic, normochromic anemia with Hct results of less than 30%. Renal failure is due to the nephrotoxicity of the IgG lambda light chains. Hypercalcemia, due to renal failure, is seen in up to 40% of patients with multiple myeloma.
1. Koutsikos J, Grigoraki V, Athanasoulis T, et al. Scintigraphy with technetium-99m methoxyisobutylisonitrile in multiple myeloma patients: correlation with the International Staging System. Hell J Nucl Med. 2006;9(3):177-180.
2. Zamagni E, Nanni C, Patriarca F, et al. A prospective comparison of 18F-fluorodeoxyglucose positron emission tomography-computed tomography, magnetic resonance imaging and whole-body planar radiographs in the assessment of bone disease in newly diagnosed multiple myeloma. Haematologica. 2007;92(1):50-55.
3. O’Connell TX, Horita TJ, Kasravi B. Understanding and interpreting serum protein electrophoresis. Am Fam Physician. 2005;71(1):105-112.