Despite apparent morphologic and immunophenotypic heterogeneity, Waldenstrom's macroglobulinemia is consistently composed of cells along a morphologic continuum of small lymphocytes, plasmacytoid lymphocytes, and plasma cells.
We studied the clinical, morphologic, and immunophenotypic features of 26 Waldenstrom's macroglobulinemia (WM) cases, each with an IgM spike of >or=3.0 g/dL. The neoplastic cells were consistently composed of a spectrum of small lymphocytes, plasmacytoid lymphocytes, and plasma cells. Bone marrow (BM) involvement ranged from 10% to 90%, showed four histologic patterns (nodular [75%], interstitial [75%], paratrabecular [42%], and diffuse [4%]), two histologic subtypes (lymphoplasmacytic [87%] and lymphoplasmacytoid [13%]), and several cytologic variants (monocytoid [n = 2], signet-ring cell [n = 2], and hairy cell leukemia-like [n = 1]). By flow cytometry (FC), all cases expressed monoclonal surface immunoglobulin, CD19, and CD20. Most cases (58%) lacked expression of CD5, CD10, and CD23. However, variants such as CD5(+)CD10(-)CD23(-) (n = 3), CD5(+)CD10(-)CD23(+) (n = 1), and CD5(-)CD10(+)CD23(+/-) (n = 2) were seen. At last follow-up, 18 of 26 patients were alive (median survival, 94 months). Causes of death included WM (n = 1), large cell lymphoma (n = 1), acute myeloid leukemia (likely therapy-related [n =2]), and nonhematologic/unknown. When individual WM cases are compared, apparent morphologic diversity is suggested. However, every WM case is comprised of cells along a morphologic continuum from small lymphocytes to plasma cells, delineating a uniform, consistent pathology. As WM shows immunophenotypic heterogeneity, morphology must be the cornerstone of the diagnosis.
Department of Laboratory Medicine, Mayo Clinic, Rochester, MN 55905, USA.
Ellen D
ED
Remstein
Curtis A
CA
Hanson
Robert A
RA
Kyle
Janice M
JM
Hodnefield
Paul J
PJ
Kurtin
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D016130:Immunophenotyping; D008214:Lymphocytes; D008297:Male; D008875:Middle Aged; D010950:Plasma Cells; D008258:Waldenstrom Macroglobulinemia / Q000276:immunology* / Q000401:mortality / Q000473:pathology*
D007075:Immunoglobulin M