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Correlation between histopathologic features and likelihood of identifying superficial dermatophytosis with periodic acid Schiff‐diastase staining: a cohort study
Author(s) -
Wang Michael Z.,
Guo Ruifeng,
Lehman Julia S.
Publication year - 2017
Publication title -
journal of cutaneous pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 75
eISSN - 1600-0560
pISSN - 0303-6987
DOI - 10.1111/cup.12865
Subject(s) - periodic acid–schiff stain , staining , diastase , pathology , cohort , medicine , correlation , dermatopathology , dermatology , mathematics , geometry
Background Periodic acid Schiff‐diastase ( PAS ‐D) staining is used routinely in dermatopathology. Conventionally, parakeratosis or intracorneal neutrophils justify use of PAS ‐D stain to identify dermatophytosis. We aimed to investigate the histopathological features of superficial dermatophytosis. Methods Skin biopsies with PAS ‐D stain were retrospectively reviewed by a blinded dermatopathologist. Histopathologic findings in cases with dermatophytosis were compared with those without. Results We studied 110 cases, of which 63 were PAS ‐D positive for dermatophytes. Dermatophytes were identified on hematoxylin and eosin (H&E) staining in 49 (77.8%) of the PAS ‐D‐positive cases. Diffuse compact orthokeratosis (79.37%, p < 0.001) and focal parakeratosis (65.08%, p = 0.03) were significantly more frequent in dermatophytosis. Intracorneal neutrophils and spongiosis were not significant findings. Fungal elements were frequently observed within compact orthokeratosis (62.0%) and parakeratosis (31.8%) but rarely within intracorneal pustules (12.7%). In some dermatophyte cases, intracorneal neutrophils (47.6%) or parakeratosis (17.5%) were absent. Conclusions Compact orthokeratosis or focal parakeratosis justifies PAS ‐D staining, whereas the absence of intracorneal neutrophils or parakeratosis is insufficient to exclude dermatophytosis. Results indicate that having a low threshold to perform PAS‐D stain is justified. PAS‐D stain may be deferred until H&E slides have been evaluated.