Abstract

Background: Gottron’s papules and Gottron’s sign are found in up to 70% of dermatomyositis (DM) patients. However, only a few reports with small cohorts have been published that describe their histopathologic features. In these reports, classic histologic DM features like interface dermatitis, dyskeratosis, increased dermal mucin are inconsistently present. We aimed to assess the histopathologic features of biopsies from Gottron’s papules/sign in a relatively large, tertiary care center DM cohort. Methods: Biopsies from Gottron’s papules/sign in DM patients between 2004-2022 were identified from our institution’s pathology archives. DM diagnosis was confirmed in all patients. Additionally, we ensured included biopsies were performed due to rash concerning for DM. Results: Histologic features of 36 biopsies from 33 unique patients were reviewed. The primary reaction pattern was interface dermatitis (28/36; 78%). Dyskeratosis was noted in the majority of cases (30/36; 83%). Mucin deposition in the dermis was found in 23 cases (64%). . Twenty-three biopsies (64%) demonstrated both interface dermatitis and increased dermal mucin and only 17 (47%) demonstrated interface dermatitis, increased dermal mucin, and dyskeratotic keratinocytes. Conclusion: Although most Gottron’s papules and Gottron’s sign typically exhibit some hallmark histologic features of DM, the percentage displaying either interface dermatitis, dyskeratosis, or mucin deposition is lower than what has been reported in lesional DM skin from other anatomic locations. Furthermore, relatively few cases displayed all three major histologic features. This suggests pathologists should not be too dismissive when histologic findings are relatively lacking in acral skin biopsies from patients being evaluated for DM.

Financial Disclosure:
No current or relevant financial relationships exist.