M components associated with lymphoma: a review of 62 cases.

Sixty-two of 1242 patients with M components were found to have lymphoma. There were 33 patients with immunoglobulin M(IgM), 20 WITH IgG, 5 with IgA, and one patient with Bence Jones protein M components. Three patients had biclonal gammopathy. The types of lymphoma were: lymphocytic, 31; histiocytic, 12; mixed cell, 4; stem cell, 2; Burkitt's, 1; Hodgkin's disease, 9; and unclassified, 3. All patients were in stages III or IV of lymphoma, and the average duration of disease was 29.3 months when M components were detected. Anemia, abnormal peripheral blood lymphocytes, and lymphomatous involvement of the bone marrow were especially common among patients with IgM M components. Osteolytic lesions were found in 12 patients and osteosclerotic lesions in one. A second malignancy occurred in eight patients. The level of M component was below 1.0 gm/dl in 55 per cent of patients. Significant suppression of normal immunoglobulin levels in the serum was noted in 4 and 16 patients with IgG and IgM components, respectively. Bence Jones proteinuria was found in 19 per cent, cryoglobulinemia in 11 per cent, and cold agglutinins, all of anti-i specificity, in 10 per cent of the patients. Most of the M components decreased during therapy. Only two M components gradually increased. The mean survival of 39 patients who died was 10.4 months. The living patients have been followed for a mean period of 21.2 months. The presence of M components in lymphoma may suggest B cell origin of the tumor but the coexistence of plasma cell dyscrasia cannot be ruled out.