Characterization of tissue findings in bone marrow biopsy specimens with small monoclonal B-cell populations.
OBJECTIVE
Bone marrows (BMs) with incidentally identified, small monotypic B-cell populations (MBPs) were evaluated.


METHODS
BM aspirates with MBPs representing 5% or less of total events by flow cytometry, less than 5.0 × 10(9)/L B cells in blood, and no history of lymphoma or MBP with a different phenotype from prior lymphoma were selected. Clinical, immunophenotypic, and histologic findings were evaluated.


RESULTS
Forty-one of 3,052 BMs had MBPs at 5% or less of total events (median, 1%); 17 were females and 24 were males aged 30 to 87 years (median, 73 years). The MBPs were CD5- in 24, CD5+ resembling chronic lymphocytic leukemia (CLL) in 13, and CD5+ unlike CLL in four. Eighteen of 40 had lymphoid aggregates (LAs) with mostly T cells or a mixture of B and T cells, but three cases had B-cell-rich LAs.


CONCLUSIONS
Unlike monoclonal B lymphocytosis in blood, MBPs in BMs were more commonly CD5-. Forty-five percent of BMs had LAs; none were interpreted as lymphoma, although three were suspicious for B-cell lymphoma.
Dept of Pathology, Northwestern University Feinberg Medical School, 251 Huron St, Feinberg 7-208, Chicago, IL 60611; bpnelson@northwestern.edu.
Beverly P
BP
Nelson
Anmaar
A
Abdul-Nabi
Charles
C
Goolsby
Jane
J
Winter
LoAnn
L
Peterson
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology; D001706:Biopsy; D001853:Bone Marrow / Q000276:immunology / Q000473:pathology*; D018956:CD5 Antigens / Q000276:immunology; D005260:Female; D006801:Humans; D016130:Immunophenotyping / Q000379:methods; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000175:diagnosis / Q000276:immunology / Q000473:pathology*; D016393:Lymphoma, B-Cell / Q000175:diagnosis / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged
D018956:CD5 Antigens
Flow cytometry; Hematopathology; Immunopathology