title: Interobserver variability on the histopathologic diagnosis of cutaneous melanoma and other pigmented skin lesions.
abstract: OBJECTIVE
  To assess the interobserver agreement on the diagnosis and classification of cutaneous melanoma.
  
  
  METHODS
  A set of 140 slides of cutaneous melanoma, including a small subset of benign pigmented skin lesions, were circulated to four experienced histopathologists. The kappa statistic for multiple ratings per subject was calculated using the method described by Fleiss.
  
  
  RESULTS
  The kappa value on the diagnosis of cutaneous melanoma versus benign lesions was 0.61. There was some discordance on the diagnosis in 37 of 140 cases (26%). For the histopathologic classification of cutaneous melanoma, the highest kappa values were attained for Breslow thickness (kappa = 0.76) and presence of ulceration (kappa = 0.87). The agreement was generally poor for other histologic features, such as level of dermal invasion (kappa = 0.38), presence of regression (kappa = 0.27), and lymphocytic infiltration (kappa = 0.27).
  
  
  CONCLUSIONS
  Our study suggests considerable disagreement among pathologists on the diagnosis of melanoma versus other pigmented lesions. Tumor thickness and presence of ulceration are the most reproducible histologic features of cutaneous melanoma.
authors.affiliation: Servizio di Epidemiologia Clinica e Servizio di Istopatologia, Istituto Dermopatico dell'Immacolata-Istituto di Ricovero E Cura A Carattere Scientifico, Rome, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Corona
authors.forename: A
authors.initials: A
authors.lastname: Mele
authors.forename: M
authors.initials: M
authors.lastname: Amini
authors.forename: G
authors.initials: G
authors.lastname: De Rosa
authors.forename: G
authors.initials: G
authors.lastname: Coppola
authors.forename: P
authors.initials: P
authors.lastname: Piccardi
authors.forename: M
authors.initials: M
authors.lastname: Fucci
authors.forename: P
authors.initials: P
authors.lastname: Pasquini
authors.forename: T
authors.initials: T
authors.lastname: Faraggiana
mesh_terms: D006801:Humans; D008545:Melanoma / Q000145:classification / Q000473:pathology*; D015588:Observer Variation; D010858:Pigmentation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012871:Skin Diseases / Q000473:pathology; D012878:Skin Neoplasms / Q000145:classification / Q000473:pathology*