title: Evidence of a limited intra-individual diversity of nevi: intuitive perception of dominant clusters is a crucial step in the analysis of nevi by dermatologists.
abstract: Although nevi are highly polymorphous, it has been suggested that each individual is characterized by only a few dominant patterns of nevi. Therefore, a nevus that does not fit in with these patterns, the "ugly duckling" nevus, is suspicious. Our objective was to study the intra-individual diversity of nevi, using human ability to build "perceived similarity clusters" (PSCs). Nine dermatologists had to cluster all the nevi of 80 patients into PSCs, at the clinical scale (CS) and at the dermoscopic scale (DS) (subset of 30 patients). Nine novices did the same in a subset of 11 patients. The experts identified a mean of 2.8 PSCs/patient at CS. Concordance was higher between experts than between novices at CS and at DS. Despite a trend for more PSCs at DS than at CS, the number of nevus patterns per patient remained low, regardless of the number of nevi. Inter-expert concordance permits a consensus representation of nevus diversity in each individual. Nevus diversity is limited in each patient and constitutes an individual reference system, which we can intuitively perceive. This reference is probably crucial for nevus analysis and melanoma detection and opens perspectives for computer-aided diagnostics.
authors.affiliation: Laboratory of Sciences and Information Systems, Aix-Marseille University, Marseille, France.
authors.forename: Yanal
authors.initials: Y
authors.lastname: Wazaefi
authors.affiliation: Department of Dermatology, La Timone Hospital, Marseille, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Gaudy-Marqueste
authors.affiliation: Department of Dermatology, APHP, Hospital Cochin, University Paris Descartes, Paris, France.
authors.forename: Marie-Françoise
authors.initials: MF
authors.lastname: Avril
authors.affiliation: Department of Dermatology, Hospital Clinic of Barcelona, Barcelona, Spain.
authors.forename: Joseph
authors.initials: J
authors.lastname: Malvehy
authors.affiliation: Department of Dermatology, University of Modena and Reggio Emilia, Modena, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pellacani
authors.affiliation: Department of Dermatology, Lyon Sud Hospital, Pierre Bénite, France.
authors.forename: Luc
authors.initials: L
authors.lastname: Thomas
authors.affiliation: Department of Dermatology, The Hertford British Hospital Charity, Levallois-Perret, France.
authors.forename: Raoul
authors.initials: R
authors.lastname: Triller
authors.affiliation: Department of Dermatology, La Timone Hospital, Marseille, France.
authors.forename: Yvane
authors.initials: Y
authors.lastname: Bruneu
authors.affiliation: Department of Dermatology, La Timone Hospital, Marseille, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Monestier
authors.affiliation: Department of Dermatology, La Timone Hospital, Marseille, France.
authors.forename: Marie-Aleth
authors.initials: MA
authors.lastname: Richard
authors.affiliation: Laboratory of Sciences and Information Systems, Aix-Marseille University, Marseille, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Fertil
authors.affiliation: Department of Dermatology, La Timone Hospital, Marseille, France. Electronic address: Jean-jacques.GROB@ap-hm.fr.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Grob
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D003880:Dermatology / Q000592:standards / Q000706:statistics & numerical data*; D003936:Diagnosis, Computer-Assisted / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009506:Nevus / Q000145:classification* / Q000473:pathology*; D015588:Observer Variation; D010364:Pattern Recognition, Visual; D010465:Perception; D015203:Reproducibility of Results; D012878:Skin Neoplasms / Q000145:classification* / Q000473:pathology*; D055815:Young Adult