title: Variability in mitotic figures in serial sections of thin melanomas.
abstract: BACKGROUND
  T1 melanoma staging is significantly affected by tissue sampling approaches, which have not been well characterized.
  
  
  OBJECTIVE
  We sought to characterize presence of mitotic figures across a minimum of 5 sequential sections of T1 melanomas.
  
  
  METHODS
  A cohort of T1 melanomas with either 5 (single section per slide) or 10 (2 sections per slide) sequential sections (5-μm thickness) per case were prepared and examined for mitotic figures.
  
  
  RESULTS
  In all, 44 of 82 T1 melanomas (54%) were classified as T1b. The number of sections with a mitotic figure present ranged from only 1 of 5 sections (n = 5 of 44 cases, 11.4%) to all 5 (n = 20 of 44 cases, 45.5%). A sequential approach versus a nonsequential approach did not appear to matter.
  
  
  CONCLUSIONS
  Cases were taken from a single pathology practice in the Pacific Northwest, which may not generalize to other populations in the United States.
  
  
  CONCLUSIONS
  The variation in the presence of mitotic figures within sequential sections supports reviewing 3 to 5 sections to fulfill American Joint Committee on Cancer recommendations. The prognostic significance of a T1b melanoma with a rare mitotic figure on a single section versus a T1b melanoma with mitotic figures on multiple sections deserves more attention to see if further subclassification is possible or even necessary.
authors.affiliation: Veterans Affairs Medical Center, Seattle, Washington; Department of Pathology, University of Washington School of Medicine, Seattle, Washington. Electronic address: stevanrk@gmail.com.
authors.forename: Stevan R
authors.initials: SR
authors.lastname: Knezevich
authors.affiliation: Department of Pathology, University of California at Los Angeles, Los Angeles, California.
authors.forename: Raymond L
authors.initials: RL
authors.lastname: Barnhill
authors.affiliation: Department of Pathology, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: David E
authors.initials: DE
authors.lastname: Elder
authors.affiliation: Division of Dermatology, Department of Medicine, University of Washington School of Medicine, Seattle, Washington; Dermatopathology Northwest, Bellevue, Washington.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Piepkorn
authors.affiliation: Department of Internal Medicine, University of Washington School of Medicine, Seattle, Washington.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Reisch
authors.affiliation: Department of Internal Medicine, University of Washington School of Medicine, Seattle, Washington.
authors.forename: Gaia
authors.initials: G
authors.lastname: Pocobelli
authors.affiliation: Departments of Family Medicine and Public Health and Preventive Medicine, Oregon Health and Sciences University, Portland, Oregon.
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Carney
authors.affiliation: Department of Internal Medicine, University of Washington School of Medicine, Seattle, Washington.
authors.forename: Joann G
authors.initials: JG
authors.lastname: Elmore
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D005260:Female; D006801:Humans; D008297:Male; D008499:Medical Records; D008545:Melanoma / Q000473:pathology*; D008875:Middle Aged; D008938:Mitosis; D008940:Mitotic Index / Q000379:methods* / Q000592:standards; D009367:Neoplasm Staging; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000473:pathology*; D055815:Young Adult
keywords: American Joint Committee on Cancer TNM staging; T1b; accuracy; mitosis; mitotic rate; reproducibility; variability