Histopathologic Characterization of Untreated and Treated Psoriasis: A Cross‐Sectional Study
Terese Monette O. Aquino, Mary Grace Anne A. Calvarido, Claudine Joy M. Ramos, Maria Jasmin J. Jamora, Johannes S. KernABSTRACT
Background
The histopathological presentation of psoriasis may vary depending on the timing of the biopsy, prior treatments utilized, and the presence of secondary skin changes. Consequently, dermatopathologists play a pivotal role in ensuring an accurate diagnosis, particularly when the psoriatic histopathology deviates from the classic features. This study aims to compare the prevalence of classic and non‐classic histopathologic features of psoriasis between untreated and treated psoriasis.
Methods
This is a review of 109 biopsies of psoriasis from 2015 to 2021 obtained from a single institution. The cases were reviewed by two independent dermatopathologists who were blinded to the assigned groups (untreated, n = 62, and treated, n = 47). A 20‐item histopathologic grading criterion, comprising both classic and non‐classic features of psoriasis, was used for assessment.
Results
The prevalence of both classic ( p = 0.274; CI: −0.169, 0.593) and non‐classic ( p = 0.456; CI: −0.526, 0.236) histopathologic features of psoriasis did not differ between untreated (classic = 78%, non‐classic = 27%) and treated (classic = 76%, non‐classic = 29%) groups. A comparison of each histopathologic feature did not vary between groups ( p > 0.05).
Conclusions
Psoriasis is a dynamic condition under the microscope. Classic histopathologic features of psoriasis seem to persist despite treatment. Non‐classic features may also occur regardless of the treatment status. Hence, the presence of these features should not preclude the tissue diagnosis of psoriasis.