title: Reliability of diagnosis from Mohs slides: interpersonal and intrapersonal agreement on basal cell carcinoma presence and histological subtype.
abstract: BACKGROUND
  The success of Mohs micrographic surgery (MMS) depends partly on the correct diagnosis of slides.
  
  
  OBJECTIVE
  To determine reliability of diagnosis from Mohs slides.
  
  
  METHODS
  This was a prospective study evaluating the reliability of diagnosis from Mohs slides of basal cell carcinoma (BCC) presence, BCC location on the slide and BCC subtype among six raters who independently assessed 50 Mohs slides twice with a 2-month interval. Slides were randomly selected whereby difficult-to-diagnose slides were oversampled. For each slide, a reference diagnosis was established by an expert panel. Cohen's kappa (κ) was calculated to determine levels of agreement interpersonally (rater vs. reference diagnosis) and intrapersonally (rater at T1 vs. T2). Multivariable logistic regression was used to determine independent risk factors for slides with interpersonal discordant diagnosis. The variables studied were BCC presence, whether a slide was scored as easy or difficult to diagnose, review duration of the 50 slides, profession and years of experience in diagnosis from Mohs slides.
  
  
  RESULTS
  Interpersonal and intrapersonal agreement were substantial on BCC presence (κ = 0·66 and 0·68) and moderate on BCC subtype (κ = 0·45 and 0·55). Slides that were scored as difficult to diagnose were an independent risk factor for interpersonal discordant diagnosis on BCC presence (odds ratio 3·54, 95% confidence interval 1·81-6·84).
  
  
  CONCLUSIONS
  Reliability of diagnosis from Mohs slides was substantial on BCC presence and moderate on BCC subtype. For slides that are scored difficult to diagnose, a second opinion is recommended to prevent misinterpretation and thereby recurrence of skin cancer.
authors.affiliation: Department of Dermatology, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, the Netherlands.
authors.forename: C B
authors.initials: CB
authors.lastname: van Lee
authors.affiliation: Department of Dermatology, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, the Netherlands.
authors.forename: E E F
authors.initials: EE
authors.lastname: Ip Vai Ching
authors.affiliation: Department of Biostatistics, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, the Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Nasserinejad
authors.affiliation: Department of Dermatology, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, the Netherlands.
authors.forename: H A M
authors.initials: HA
authors.lastname: Neumann
authors.affiliation: Department of Pathology, Isala Hospital, Zwolle, the Netherlands.
authors.forename: M G W
authors.initials: MG
authors.lastname: Bol
authors.affiliation: Department of Dermatology, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, the Netherlands.
authors.forename: P K
authors.initials: PK
authors.lastname: Dikrama
authors.affiliation: Department of Dermatology, Maastricht University Medical Centre, Maastricht, the Netherlands.
authors.forename: N W J
authors.initials: NW
authors.lastname: Kelleners-Smeets
authors.affiliation: Department of Pathology, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, the Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Koljenović
authors.affiliation: Department of Dermatology, Maasstad Hospital, Rotterdam, the Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Munte
authors.affiliation: Department of Pathology, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, the Netherlands.
authors.forename: V
authors.initials: V
authors.lastname: Noordhoek Hegt
authors.affiliation: Department of Dermatology, Isala Hospital, Zwolle, the Netherlands.
authors.forename: H C
authors.initials: HC
authors.lastname: de Vijlder
authors.affiliation: Department of Dermatology, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, the Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: Nijsten
authors.affiliation: Department of Dermatology, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, the Netherlands. r.vandenbos@erasmusmc.nl.
authors.forename: R R
authors.initials: RR
authors.lastname: van den Bos
mesh_terms: D002280:Basal Cell Carcinoma / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D015580:Mohs Surgery; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results; D012307:Risk Factors; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000601:surgery