The classical histopathological findings in the epidermis of pityriasis rubra pilaris (PRP) do not include acantholysis; however, acantholysis was described in several case reports and a few series of PRP with variable frequencies. We sought to establish the incidence of acantholysis in biopsies from consecutively referred PRP cases using multiple-step sections and clinicopathologic correlations.Methods:
Twenty-three biopsies from 12 consecutively referred patients with classical (type 1) PRP were studied histopathologically. Each specimen was completely step sectioned. The clinical files of the patients were also reviewed.Results:
Small foci of acantholysis were observed in some of the step sections of 5 of 23 (22%) biopsies obtained from 4 patients. Three biopsies showed suprabasal acantholysis, 1 of which also demonstrated mild dyskeratosis and 2 showed midepidermal acantholytic foci as well. The remaining 2 biopsies demonstrated midepidermal and subcorneal acantholysis, respectively. Small erosions were described in the physical examination of 2 of the 4 (50%) patients with acantholysis and in 1 of the 8 (12.5%) patients without acantholysis.Limitations:
The number of cases.Conclusions:
Small foci of acantholysis may be found in the minority of PRP biopsies, and it may be related to small erosions clinically in some patients.