“CRAB” Findings in a Patient With Fatigue and a History of Poor Appetite

Abstract

demonstrated the presence of aberrant plasma cells constituting 64% of all cells observed in the bone marrow. Imaging studies of her axial skeleton revealed lytic lesions in both humeri and femurs, and in the skull, a compression fracture of the T12 vertebra, and a plasmacytoma in her left-side sixth rib. Laboratory testing revealed normal serum electrolytes, calcium, and creatinine levels. The patient started a prolonged chemotherapeutic regimen that included 3 cycles of vincristine, adriamycin, and dexamethasone (VAD), combination therapy with Thalidomide and Decadron, and Decadron maintenance therapy. Each regimen provided only a short-term reduction in the size of her serum Mspike and in her urine free light chain excretion rate. As a prelude to an autologous stem cell transplant, the patient underwent a repeat bone marrow biopsy, SPE, and UPE. The bone marrow biopsy demonstrated 27% aberrant plasma cells, while the SPE again showed an M-spike consistent with IgG kappa (0.38 g/dL); however, the UPE of a sample from a 24-hour urine collection was negative for any intact or free light chain immunoglobulins (data not shown). The patient underwent stem cell mobilization followed by bone marrow myeloablation using high-dose melphalan therapy and stem cell transfusion. She tolerated the procedure well, requiring only administration of packed red blood cells and platelets to maintain an adequate cell count of these formed elements while engraftment was occurring.