title: Monoclonal gammopathy of undetermined significance: a new proposal of workup.
abstract: OBJECTIVE
  Diagnostic criteria for monoclonal gammopathy of undetermined significance (MGUS) require quantification of bone marrow plasma cells (BMPCs) and skeletal survey to discriminate between MGUS and multiple myeloma (MM). By contrast, recent published guidelines suggest that these procedures could be avoided in the presence of serum monoclonal spike (M-spike) of small amount (≤1.5 g/dL). Aim of this study is to better quantify the risk of missing a diagnosis of MM, not performing bone marrow aspirate and skeletal survey in patients with M-spike ≤ 1.5 g/dL asymptomatic for bone pain.
  
  
  METHODS
  We reviewed data of 2282 patients consecutively observed from January 1974 to December 2010 in our single hematology department. We considered eligible for this study 1271 patients with grade <2 NCI bone pain, confirmed to have an MGUS or an MM after extensive standardized diagnostic workup including bone marrow biopsy, skeletal bone survey and laboratory tests.
  
  
  RESULTS
  The risk of finding a BMPC infiltration ≥10% in patients with an M-spike ≤ 1.5 g/dL was very low (7.3%), although significantly different according to IgH isotype (4.7% for IgG vs. 20.5% for IgA). The risk of finding bone lesions with M-spike ≤ 1.5 g/dL was negligible (2.5%), regardless of IgH isotype.
  
  
  CONCLUSIONS
  In asymptomatic patients with M-spike of small amount (≤1.5 g/dL): (i) BMPC evaluation may be reasonably avoided in patients with IgG M-spike, while should always be part of diagnostic workup in the presence of IgA M-spike and (ii) skeletal survey, less predictive for MM, should not be routinely indicated irrespective of IgH isotype.
authors.affiliation: Division of Hematology, Fondazione IRCCS Policlinico San Matteo, University of Pavia, Pavia, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Mangiacavalli
authors.forename: Federica
authors.initials: F
authors.lastname: Cocito
authors.forename: Lara
authors.initials: L
authors.lastname: Pochintesta
authors.forename: Cristiana
authors.initials: C
authors.lastname: Pascutto
authors.forename: Virginia
authors.initials: V
authors.lastname: Ferretti
authors.forename: Marzia
authors.initials: M
authors.lastname: Varettoni
authors.forename: Patrizia
authors.initials: P
authors.lastname: Zappasodi
authors.forename: Alessandra
authors.initials: A
authors.lastname: Pompa
authors.forename: Benedetta
authors.initials: B
authors.lastname: Landini
authors.forename: Mario
authors.initials: M
authors.lastname: Cazzola
authors.forename: Alessandro
authors.initials: A
authors.lastname: Corso
mesh_terms: D000328:Adult; D001706:Biopsy; D001853:Bone Marrow / Q000276:immunology / Q000473:pathology; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D008875:Middle Aged; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D009101:Multiple Myeloma / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D010950:Plasma Cells / Q000276:immunology / Q000473:pathology; D017410:Practice Guidelines as Topic; D011859:Radiography; D012189:Retrospective Studies
chemical_list: D007070:Immunoglobulin A; D007074:Immunoglobulin G
keywords: diagnostic workup; monoclonal gammopathy of undetermined significance; myeloma