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Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma Associated With IgM Paraprotein
A Clinicopathologic Study of 26 Cases

C. Cameron Yin MD, PhD, Pei Lin MD, Dennis A. Carney MD, Beverly C. Handy MD, George Z. Rassidakis MD, PhD, Joan H. Admirand MD, Michael J. Keating MD, L. Jeffrey Medeiros MD
DOI: http://dx.doi.org/10.1309/FDGWB5C2MYRYXH2E 594-602 First published online: 1 April 2005


We studied the clinicopathologic, immunophenotypic, and cytogenetic features of 26 patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) associated with serum IgM paraprotein. The study group (16 men; 10 women; median age, 64 years; range, 40–82 years) represents approximately 2.5% of CLL/SLL cases at our institution. The paraprotein level ranged from 1 to 14 g/L (median, 4 g/L). Neoplasms in bone marrow were composed of small round lymphocytes arranged in nodular (n = 6), diffuse (n = 5), interstitial (n = 5), or mixed (n = 10) patterns. All cases were positive for monotypic surface immunoglobulin light chain, IgM/IgD, CD5, CD19, CD20, and CD23. CD11c (14/20 [70%]), CD79b (11/19 [58%]), FMC-7 (11/26 [42%]), CD22 (8/20 [40%]), and ZAP-70 (6/19 [32%]) were expressed in subsets of cases. Of 17 bone marrow specimens assessed by conventional cytogenetics, 6 were abnormal and 11 were diploid. The overall survival of this group (median follow-up, 24 months) was not significantly different from that for an age-, sex-, and stage-matched group of 52 CLL/SLL patients without IgM paraprotein (P = .60). We conclude that CLL/SLL cases with serum IgM paraprotein are similar to other CLL/SLL cases in their clinicopathologic and immunophenotypic features.

Key Words:
  • Chronic lymphocytic leukemia/small lymphocytic lymphoma
  • Serum IgM
  • Plasmacytoid lymphocytes
  • ZAP-70