A new case of IgE myeloma.

We report a case of IgE myeloma in a 78-year-old woman who presented with bone pain in the shoulder and hip and progressive weakness. Except for hypercalcemia, routine chemistry values were within normal limits. Hemoglobin was decreased and the leukocyte count slightly increased. Plasma cells were not observed in the peripheral blood. Serum protein electrophoresis showed a monoclonal protein in the beta-globulin fraction. Immunofixation confirmed the presence of an IgE kappa monoclonal protein. A bone marrow biopsy revealed an interstitial and nodular infiltration of abnormal plasma cells comprising 60% of nucleated cells present. Skeletal roentgenograms and bone scans of this patient showed osteolytic lesions and osteopenia of the thoracic and lumbar spine and osteolytic destruction of the right half of the sacrum. Flow-cytometric analysis of mononuclear cells isolated from peripheral blood showed that 15% of the lymphocytes bound IgE. Using cell-surface markers, we identified 45% of the IgE-positive cells as natural killer cells. Similar results have been found in other diseases marked by increased IgE. The clinical, radiological, and laboratory findings for this patient are compared with previously reported cases of IgE and other types of myeloma.