Worsening low back pain
Our patient attributed his back pain to a recent fall, but his lab work and a sagittal CT pointed us in another direction.
Dx: Multiple myeloma
The sagittal CT reconstruction in bone windows of the thoracolumbar spine (FIGURE 1) revealed multiple lucent foci throughout the osseous structures, with an anterior compression deformity of the L2 vertebral body. A subsequent skeletal survey showed a diffuse salt and pepper pattern affecting most of the osseous structures, with additional lytic lesions in the calvarium and extremities.
Following inpatient admission, the patient underwent a bone marrow biopsy that showed 90% marrow plasma cells (FIGURE 2). Serum protein electrophoresis (SPEP) and immunofixation electrophoresis revealed an elevated monoclonal protein of 7.52 g/dL IgG kappa, prompting us to diagnose multiple myeloma.
FIGURE 2
Bone marrow smear reveals 90% marrow plasma cells
Patients are typically much older
Multiple myeloma is a malignant proliferation of plasma cells derived from a single clone and accounts for 13% of all hematologic malignancies in Caucasians and 33% in African Americans. As with most hematopoeitic malignancies, the incidence of multiple myeloma increases with age, with the median age at diagnosis estimated at 69 years. In addition, 47% of multiple myeloma patients are >70 years of age, and 75% are >60.1
Clinical findings in multiple myeloma vary from asymptomatic patients whose disease is discovered incidentally to patients presenting with life-threatening symptoms. In a recent study of more than 1000 newly diagnosed patients, the most common presenting symptoms were bone pain (58%), fatigue (32%), and weight loss (24%).2 Tumor cells, tumor products (ie, monoclonal immunoglobulin protein), and host response to both elements account for other focal and systemic symptoms, including bone fracture, anemia, renal failure, vascular manifestations of hyperviscosity, hypercalcemia, and increased susceptibility to infection.
This presentation, in conjunction with radiological evidence of lytic bone lesions, increased total serum protein concentration, and a monoclonal protein in the urine or serum, constitutes the hallmark findings of multiple myeloma.
