title: Diagnostic and clinical considerations in concomitant bone marrow involvement by plasma cell myeloma and chronic lymphocytic leukemia/monoclonal B-cell lymphocytosis: a series of 15 cases and review of literature.
abstract: BACKGROUND
  Plasma cell myeloma and chronic lymphocytic leukemia are both common hematologic malignancies, sharing many epidemiologic features. Concomitant detection of the 2 conditions poses special diagnostic challenges for the pathologist.
  
  
  OBJECTIVE
  To describe the pathologic findings in cases of concomitant bone marrow involvement by myeloma and CD5(+) monoclonal B cells and to outline the differential diagnostic possibilities, suggest a workup for correct diagnosis, and examine clinical outcome.
  
  
  METHODS
  Fifteen cases that met the diagnostic criteria were identified from pathology databases at 4 participating institutions. Morphologic findings were reviewed, additional immunohistochemical stains performed, and flow cytometric, cytogenetic, and relevant laboratory and clinical information was summarized. Previously published cases were searched from electronic databases and cross-references.
  
  
  RESULTS
  Most patients (13 of 15) were older males. Often (11 of 15) they presented clinically with myeloma, yet had both monotypic plasma cells and B cells in the diagnostic marrow. In 4 patients, myeloma developed 24 months or later after chronic lymphocytic leukemia. In 7 patients, myeloma and CD5(+) B cells showed identical immunoglobulin light-chain restriction. Primary differential diagnoses include lymphoplasmacytic lymphoma, marginal zone lymphoma, and chronic lymphocytic leukemia with plasmacytoid differentiation. CD56 and/or cyclin D1 expression by plasma cells was helpful for correct diagnosis. Most patients in our cohort and published reports were treated for plasma cell myeloma.
  
  
  CONCLUSIONS
  Concomitant detection of myeloma and chronic lymphocytic leukemia in the bone marrow is a rare event, which must be carefully differentiated from lymphomas with lymphoplasmacytic differentiation for correct treatment.
authors.affiliation: Department of Pathology, Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Alley
authors.forename: Endi
authors.initials: E
authors.lastname: Wang
authors.forename: Cherie H
authors.initials: CH
authors.lastname: Dunphy
authors.forename: Jerald Z
authors.initials: JZ
authors.lastname: Gong
authors.forename: Chuanyi M
authors.initials: CM
authors.lastname: Lu
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Boswell
authors.forename: James
authors.initials: J
authors.lastname: Burchette
authors.forename: Anand S
authors.initials: AS
authors.lastname: Lagoo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001402:B-Lymphocytes / Q000378:metabolism / Q000473:pathology*; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D001853:Bone Marrow / Q000473:pathology*; D018956:CD5 Antigens / Q000378:metabolism; D002999:Clone Cells; D003937:Diagnosis, Differential; D005260:Female; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000032:analysis; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D008218:Lymphocytosis / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D018442:Lymphoma, B-Cell, Marginal Zone / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism; D016609:Neoplasms, Second Primary / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism; D010950:Plasma Cells / Q000378:metabolism / Q000473:pathology*; D008258:Waldenstrom Macroglobulinemia / Q000175:diagnosis
chemical_list: D014408:Biomarkers, Tumor; D018956:CD5 Antigens; D007147:Immunoglobulin Light Chains