title: Guidelines for pathologic diagnosis of malignant mesothelioma: 2012 update of the consensus statement from the International Mesothelioma Interest Group.
abstract: BACKGROUND
  Malignant mesothelioma (MM) is an uncommon tumor that can be difficult to diagnose.
  
  
  OBJECTIVE
  To provide updated practical guidelines for the pathologic diagnosis of MM.
  
  
  METHODS
  Pathologists involved in the International Mesothelioma Interest Group and others with an interest in the field contributed to this update. Reference material includes peer-reviewed publications and textbooks.
  
  
  CONCLUSIONS
  There was consensus opinion regarding (1) distinction of benign from malignant mesothelial proliferations (both epithelioid and spindle cell lesions), (2) cytologic diagnosis of MM, (3) key histologic features of pleural and peritoneal MM, (4) use of histochemical and immunohistochemical stains in the diagnosis and differential diagnosis of MM, (5) differentiation of epithelioid MM from various carcinomas (lung, breast, ovarian, and colonic adenocarcinomas, and squamous cell and renal cell carcinomas), (6) diagnosis of sarcomatoid mesothelioma, (7) use of molecular markers in the diagnosis of MM, (8) electron microscopy in the diagnosis of MM, and (9) some caveats and pitfalls in the diagnosis of MM. Immunohistochemical panels are integral to the diagnosis of MM, but the exact makeup of panels used is dependent on the differential diagnosis and on the antibodies available in a given laboratory. Immunohistochemical panels should contain both positive and negative markers. It is recommended that immunohistochemical markers have either sensitivity or specificity greater than 80% for the lesions in question. Interpretation of positivity generally should take into account the localization of the stain (eg, nuclear versus cytoplasmic) and the percentage of cells staining (>10% is suggested for cytoplasmic membranous markers). These guidelines are meant to be a practical reference for the pathologist.
authors.affiliation: Department of Pathology, University of Chicago, Chicago, IL 60637, USA. aliya.husain@uchospitals.edu
authors.forename: Aliya N
authors.initials: AN
authors.lastname: Husain
authors.forename: Thomas
authors.initials: T
authors.lastname: Colby
authors.forename: Nelson
authors.initials: N
authors.lastname: Ordonez
authors.forename: Thomas
authors.initials: T
authors.lastname: Krausz
authors.forename: Richard
authors.initials: R
authors.lastname: Attanoos
authors.forename: Mary Beth
authors.initials: MB
authors.lastname: Beasley
authors.forename: Alain C
authors.initials: AC
authors.lastname: Borczuk
authors.forename: Kelly
authors.initials: K
authors.lastname: Butnor
authors.forename: Philip T
authors.initials: PT
authors.lastname: Cagle
authors.forename: Lucian R
authors.initials: LR
authors.lastname: Chirieac
authors.forename: Andrew
authors.initials: A
authors.lastname: Churg
authors.forename: Sanja
authors.initials: S
authors.lastname: Dacic
authors.forename: Armando
authors.initials: A
authors.lastname: Fraire
authors.forename: Francoise
authors.initials: F
authors.lastname: Galateau-Salle
authors.forename: Allen
authors.initials: A
authors.lastname: Gibbs
authors.forename: Allen
authors.initials: A
authors.lastname: Gown
authors.forename: Samuel
authors.initials: S
authors.lastname: Hammar
authors.forename: Leslie
authors.initials: L
authors.lastname: Litzky
authors.forename: Alberto M
authors.initials: AM
authors.lastname: Marchevsky
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Nicholson
authors.forename: Victor
authors.initials: V
authors.lastname: Roggli
authors.forename: William D
authors.initials: WD
authors.lastname: Travis
authors.forename: Mark
authors.initials: M
authors.lastname: Wick
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000473:pathology; D003937:Diagnosis, Differential; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008654:Mesothelioma / Q000175:diagnosis* / Q000473:pathology; D000086002:Mesothelioma, Malignant; D010997:Pleural Neoplasms / Q000175:diagnosis* / Q000473:pathology