Recently, polarized microscopy was reported as helpful in the evaluation of alopecia biopsy specimens.
We sought to determine the usefulness of polarized microscopy relative to elastic tissue staining and fluorescent microscopy.
Histologic sections from 60 alopecia specimens were evaluated to determine the pattern of elastic tissue in elastic van Gieson–stained sections. Comparable hematoxylin-eosin sections were examined under a fluorescent microscope to determine the elastic tissue pattern and examined under polarized microscopy to determine the pattern of birefringence.
Elastic van Gieson staining demonstrated high sensitivity (1.0) and high specificity (1.0) for the identification of nonscarring alopecia. In 54 of 60 cases, fluorescent microscopy demonstrated an identical pattern of elastic tissue. High background eosin fluorescence made it impossible to interpret the elastic tissue pattern in the remaining 6 specimens. Strong birefringence in dermal collagen sparing fibrous tracts had high specificity (1.0) but lower sensitivity (0.59). Strong collagen birefringence within the dermis and broad fibrous tracts were present in all 6 cases of central centrifugal cicatricial alopecia.
Elimination of the 6 uninterpretable specimens with high background fluorescence from our calculations may be a source of bias, as these cases could potentially all have been either negative or positive.
Elastic tissue staining is the most reliable means to determine the pattern of scarring in alopecia biopsy specimens. In most cases, fluorescent microscopy of hematoxylin-eosin sections shows an identical pattern. Although a pattern of collagen birefringence on polarized microscopy distinctly sparing fibrous tract is specific for nonscarring alopecia, not all cases of nonscarring alopecia demonstrate this pattern. Strong collagen birefringence within both the dermis and fibrous tracts suggests a diagnosis of central centrifugal cicatricial alopecia.Le texte complet de cet article est disponible en PDF.
Key words : alopecia, biopsy, cicatricial, elastic, fluorescent, histology, polarized, scar
Abbreviations used : CCCA, EVG, FFA, H&E, LPP, NPV, PPV
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| Conflicts of interest: None declared.
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