title: [Cutaneous lymphoproliferations: proposal for the use of diagnostic algorithms based on 2760 cases of cutaneous lymphoproliferations taken from the INCa networks (LYMPHOPATH and GFELC) over a two-year period].
abstract: BACKGROUND
  Taking as a base our retrospective study of 2760 cases of cutaneous lymphoproliferations from the LYMPHOPATH and GFELC networks, we analyzed the doubtful and discordant cases between non-expert and expert pathologists, and the interest of clinicopathological confrontation.
  
  
  METHODS
  We defined the main diagnostic difficulties presented by cutaneous lymphoproliferations. We then designed and tested the algorithms on 20 random cases with 20 pathologists, in order to be used by any pathologist (not necessarily specialised in dermatopathology).
  
  
  RESULTS
  The problematic differential diagnoses most frequently encountered are the following: MF or reactive dermatose; lymphoma without any other precision or reactive infiltrate; small B cell lymphoproliferation: lymphoma or reactive infiltrate; phenotyping of large B cell lymphoproliferation. We also analyzed less common problematic differential diagnoses, on the grounds that they are over- or under- diagnosed. Our test had a 72% success rate among the 20 randomly tested cases. The use of several algorithms for the same case is possible.
  
  
  CONCLUSIONS
  Our study shows that an expert second-opinion is of interest in the area of cutaneous lymphoproliferations. A second opinion is useful for distinguishing a small B cell lymphoma from a HLR, and for defining a final diagnosis when the first pathologist doubts between lymphoma and reactive infiltrate. However, we demonstrate that for the problem MF or reactive dermatose, an initial clinicopathological confrontation produces more results than a second-opinion pathology review.
  
  
  CONCLUSIONS
  This is the first study of cutaneous lymphoproliferations that, without excluding reactionary infiltrates, concentrates on doubtful and discordant diagnoses between non expert and expert pathologists, and which has produced tested diagnostic algorithms.
authors.affiliation: Service de pathologie, hôpital Haut-Lévêque, CHU de Bordeaux, avenue de Magellan, 33604 Pessac cedex, France. Electronic address: emiliell@hotmail.com.
authors.forename: Émilie
authors.initials: É
authors.lastname: Laban
authors.affiliation: Service de dermatologie, hôpital Haut-Lévêque, CHU de Bordeaux, avenue de Magellan, 33604 Pessac cedex, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Beylot-Barry
authors.affiliation: Département de pathologie, hôpital Henri-Mondor, 51, avenue du Maréchal-de-Lattre-de-Tassigny, 94010 Créteil cedex, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Ortonne
authors.affiliation: Service de pathologie, hôpital Saint-Louis, 1, avenue Claude-Vellefaux, 75475 Paris cedex 10, France.
authors.forename: Maxime
authors.initials: M
authors.lastname: Battistella
authors.affiliation: Service de pathologie, hôpital Cochin, 27, rue du Faubourg-Saint-Jacques, pavillon Gustave-Roussy, 75679 Paris cedex 14, France.
authors.forename: Agnes
authors.initials: A
authors.lastname: Carlotti
authors.affiliation: Service de pathologie, hôpital Trousseau, CHRU de Tour, avenue de la République, 37170 Chambray-les-Tours, France.
authors.forename: Anne
authors.initials: A
authors.lastname: de Muret
authors.affiliation: Département de pathologie, hôpital Henri-Mondor, 51, avenue du Maréchal-de-Lattre-de-Tassigny, 94010 Créteil cedex, France.
authors.forename: Janine
authors.initials: J
authors.lastname: Wechsler
authors.affiliation: Service de pathologie, centre hospitalier Lyon Sud, 165, chemin du Grand-Revoyet, pavillon 3D, 69495 Pierre-Bénite cedex, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Balme
authors.affiliation: Service de pathologie, plateau technique de biologie, CHU de Dijon, 2, rue A.-Ducoudray, BP 37013, 21070 Dijon cedex, France.
authors.forename: Tony
authors.initials: T
authors.lastname: Petrella
authors.affiliation: Département de pathologie, institut universitaire du cancer de Toulouse, Oncopole, 1, avenue Irène-Joliot-Curie, 31059 Toulouse cedex 9, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Lamant
authors.affiliation: Service de pathologie, CHU de Poitiers, 2, rue de la Milétrie, La Milétrie, BP 577, 86021 Poitiers cedex, France.
authors.forename: Éric
authors.initials: É
authors.lastname: Frouin
authors.affiliation: Service de biologie des tumeurs, hôpital Haut-Lévêque, CHU de Bordeaux, avenue de Magellan, 33604 Pessac cedex, France.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Merlio
authors.affiliation: Service de pathologie, hôpital Haut-Lévêque, CHU de Bordeaux, avenue de Magellan, 33604 Pessac cedex, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Vergier
mesh_terms: D000328:Adult; D000465:Algorithms; D003937:Diagnosis, Differential; D006801:Humans; D008223:Lymphoma / Q000473:pathology*; D008232:Lymphoproliferative Disorders / Q000473:pathology*; D008875:Middle Aged; D012189:Retrospective Studies; D012871:Skin Diseases / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*; D013997:Time Factors
keywords: Aide au diagnostic; Algorithme diagnostique; Bilan réseau maladies rares (INCa); Clinicopathological confrontation; Confrontation anatomoclinique; Cutaneous lymphoma; Diagnostic algorithm; Help to diagnosis; Infiltrat lymphoïde réactionnel; Lymphome cutané; Rare diseases network (INCa); Reactive lymphoid infiltrate