Contributed by Marian Rollins-Raval, MD, MPH
Published on line in June 2007
The patient is a 62 year-old male with a history of trauma falling on an outstretched hand. He had been complaining of pain in the right clavicular region. Although a chest radiograph was inconclusive, the CT scan (Figures 1a and 1b) demonstrated permeative changes involving the right clavicle with a subacute pathologic fracture of the mid shaft of the right clavicle. There was a diffuse abnormality of all bones with generalized osteoporosis and permeative changes suggestive of myeloma, leukemia and other marrow infiltrative processes. A CT guided fine needle aspiration was performed and showed cytomorphologic and immunophenotypic evidence of a κ-restricted plasmacytoma.
A serum protein electrophoresis and immunofixation (Figures 2 and 3) were performed showing no monoclonal proteins in the serum. A CBC, calcium and creatinine were also normal.
He was referred to the Multiple Myeloma program to distinguish between multiple myeloma and solitary plasmacytoma. A bone marrow biopsy from the right hip was performed showing variably cellular bone marrow with trilineage hematopoiesis, increased plasma cells and lymphoid aggregates (Figures 4 and 5).
Immunohistochemical stains on the marrow biopsy demonstrated an increased number of CD138 positive plasma cells that κ light chain restricted (Figures 6 and 7), cyclin-D1 positive. This population comprised approximately 75% of the total cellularity and 40% of the biopsy area. The lymphoid aggregates were composed of predominantly T-cells with few admixed B-cells and were favored to be reactive in nature. Flow cytometric studies performed on the bone marrow aspirate demonstrated approximately 11% CD138 plasma cells that were also CD38 positive and demonstrated cytoplasmic κ light chain restriction. Also present on flow cytometry were admixed moderate numbers of heterogenous T-cells, a few polytypic B-cells, a few natural killer cells and a few natural killer-like T-cells. Cytogenetic studies were negative.
On the same day as the biopsy, a serum free light chain (sFLC) assay was performed showing a concentration of free light chains in serum that were determined as κ=172mg/L (normal: 3.3-19.4 mg/L) and λ=5.44mg/L (normal: 5.7-26.3 mg/L) with a κ/λ ratio of 31.62 (normal: 0.26-1.65). Also, a β2-microglobulin was performed which was high at 2.31 (<1.86mg/ml).
Due to the extent of the bony disease and 75% infiltration of his bone marrow, the clinician felt that treatment should be started sooner rather than later. The patient was started on IV bisphosphonate monthly to treat bony disease, which may have been confounding the apparent advanced clinical stage of the neoplastic disease. He was also scheduled to be started on thalidomide and dexamethasone.
A month and a half after the sFLC assay is performed, a second demonstrates a concentration of free light chains in serum that were determined as κ=122mg/L (normal: 3.3-19.4 mg/L) and λ =10.9mg/L (normal: 5.7-26.3 mg/L) with a κ/λ ratio of 11.2 (normal: 0.26-1.65). A second β2-microglobulin was also performed which had decreased to 2.13mg/ml.