title: Epidermal thickness measured by light microscopy: a methodological study.
abstract: OBJECTIVE
  Epidermal thickness is frequently measured by light microscopy. The preservation and staining methods may alter the proportions of the specimens and thereby influence the measurements. The aim of the present study was to describe: 1) a standardized light microscopic method to quantify the thicknesses of the stratum corneum and the cellular epidermal layers, 2) the variations according to preparation and staining techniques, and 3) the observer variability.
  
  
  METHODS
  One hundred and sixty skin biopsies from 67 human volunteers were included. The cellular epidermis and the stratum corneum were estimated in sections preserved by freezing and subsequent preparation with cryostat or formalin-paraffin techniques. The slides were stained with haematoxylin-eosin or er-ythrocin, and thicknesses of the stratum corneum and the cellular epidermis were measured by a calibrated ruler and an ocular grid, respectively.
  
  
  RESULTS
  The formalin fixation gave slightly higher values for the cellular epidermis than the cryostat technique. In comparison to erythrocin staining, haematoxylin-eosin gave a significantly thinner stratum corneum. No significant inter- or intra-observer variation was found for the thickness of the stratum corneum assessed twice by two experienced observers. However, the two observers differed slightly from each other on the thickness of the cellular epidermis.
  
  
  CONCLUSIONS
  It is found that thickness measurements of the stratum corneum and the cellular epidermis are reliably performed on cryostatic cut sections stained with haematoxylin-eosin.
authors.affiliation: Department of Pathology, Sønderborg Sygehus, SønderborgDepartment of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Therkildsen
authors.affiliation: Department of Pathology, Sønderborg Sygehus, SønderborgDepartment of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: M
authors.initials: M
authors.lastname: Haedersdal
authors.affiliation: Department of Pathology, Sønderborg Sygehus, SønderborgDepartment of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Lock-Andersen
authors.affiliation: Department of Pathology, Sønderborg Sygehus, SønderborgDepartment of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: F
authors.initials: F
authors.lastname: de Fine Olivarius
authors.affiliation: Department of Pathology, Sønderborg Sygehus, SønderborgDepartment of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: T
authors.initials: T
authors.lastname: Poulsen
authors.affiliation: Department of Pathology, Sønderborg Sygehus, SønderborgDepartment of Dermatology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: H C
authors.initials: HC
authors.lastname: Wulf
keywords: comparative study; epidermis; human; skin thickness; stratum corneum