title: Lymphoplasmacytic Lymphoma With a Non-IgM Paraprotein Shows Clinical and Pathologic Heterogeneity and May Harbor MYD88 L265P Mutations.
abstract: OBJECTIVE
  Lymphoplasmacytic lymphoma (LPL) with non-immunoglobulin M (IgM) paraproteinemia remains poorly understood. The goal of this study was to investigate the clinicopathologic features of LPL in the bone marrow in patients with immunoglobulin G (IgG) or immunoglobulin A (IgA) paraproteins and evaluate MYD88 L265P mutation status to determine the relationship of these cases to Waldenström macroglobulinemia (WM).
  
  
  METHODS
  Bone marrows from LPL cases with IgG or IgA paraproteins diagnosed between January 1, 2007, and June 30, 2014, were retrieved from the clinical archive. Clinicopathologic features were retrospectively reviewed. MYD88 L265P mutation status was assessed by allele-specific polymerase chain reaction prospectively on all cases.
  
  
  RESULTS
  Of 27 cases, four were reclassified as multiple myeloma, all MYD88 mutation negative. MYD88 L265P mutations were present in 10 (43%) of 23 remaining cases. No association between MYD88 status and bone marrow morphologic or phenotypic features, including the presence of Dutcher bodies, mast cells, expression of CD19 by plasma cells, or hemosiderin, was identified, although these features were present in a subset of cases, similar to WM. Clinical features of WM such as hyperviscosity were uncommon in this group and did not correlate with MYD88 status.
  
  
  CONCLUSIONS
  Non-IgM LPLs are a clinically and pathologically heterogeneous group and often harbor MYD88 L265P mutation, albeit at a lower rate than classic WM. MYD88 status does not correlate with any specific pathologic or clinical manifestations.
authors.affiliation: From the Division of Hematopathology rebecca.king98@gmail.com.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: King
authors.affiliation: Department of Hematology.
authors.forename: Wilson I
authors.initials: WI
authors.lastname: Gonsalves
authors.affiliation: Department of Hematology.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Ansell
authors.affiliation: Division of Laboratory Genetics, Mayo Clinic, Rochester, MN.
authors.forename: Patricia T
authors.initials: PT
authors.lastname: Greipp
authors.affiliation: From the Division of Hematopathology.
authors.forename: Lori A
authors.initials: LA
authors.lastname: Frederick
authors.affiliation: From the Division of Hematopathology.
authors.forename: David S
authors.initials: DS
authors.lastname: Viswanatha
authors.affiliation: From the Division of Hematopathology.
authors.forename: Rong
authors.initials: R
authors.lastname: He
authors.affiliation: Department of Hematology.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kyle
authors.affiliation: Department of Hematology.
authors.forename: Morie A
authors.initials: MA
authors.lastname: Gertz
authors.affiliation: Department of Hematology.
authors.forename: Prashant
authors.initials: P
authors.lastname: Kapoor
authors.affiliation: From the Division of Hematopathology.
authors.forename: William G
authors.initials: WG
authors.lastname: Morice
authors.affiliation: From the Division of Hematopathology.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Howard
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics*; D010266:Paraproteins / Q000276:immunology; D012189:Retrospective Studies; D008258:Waldenstrom Macroglobulinemia / Q000235:genetics* / Q000276:immunology* / Q000473:pathology*
chemical_list: D007070:Immunoglobulin A; D007074:Immunoglobulin G; C507779:MYD88 protein, human; D053594:Myeloid Differentiation Factor 88; D010266:Paraproteins
keywords: Bone marrow; IgA; IgG; Lymphoplasmacytic lymphoma; MYD88; Non-IgM; Paraprotein; Waldenström macroglobulinemia