RESUMO
Objective:To identify dermatopathological features of patients with dermatomyositis (DM) and analyze its correlation with cutaneous diseases activity.Methods:The clinical data and skin biopsies of 48 patients were collected. The relevance was analyzed using Spearman's correlation analysis. The two groups were compared using Chi-square test or Fisher's exact test. Multi-factors line regression model was established to analyze the relationship between cutaneous disease activity and dermatopathological features.Results:The most common dermatopathological feature was perivascular inflammation (37 cases, 88%), followed by epidermal atrophy (22 cases, 52%) and melanocyte loss (20 cases, 48%), basal vacuolization (15 cases, 36%). The incidence of basal vacuolization ( χ2=9.110, P=0.022), interface dermatitis ( χ2=11.672, P=0.005) and mucin deposition ( χ2=7.795, P=0.029) were significantly different in patients with myositis specific antibody (MSA) subgroup. The patients with positive tranional intermediary factor-1 (anti-TIF1-γ) antibody had higher incidence of interface dermatitis and basal vacuolization, and patients with melanoma differentiation-associated gene 5 (anti-MDA5) antibody had lower incidence of interface dermatitis. Interface dermatitis was positively associated with epidermal atrophy ( r=0.371, P=0.016) and parakeratosis ( r=0.316, P=0.041). Pigment inco-ntinence was positively associated with basal vacuolization ( r=0.384, P=0.012). Multi-factor line regression showed interface dermatitis was positively related to cutaneous disease area and severity index (CDASI). Conclusion:The dermatopathological features is different in subgroup of patients with DM ( β=10.295, P=0.004). Interface dermatitis is a marker of cutaneous disease activity, and its pathogenesis may be different from that of perivascular inflammation. Keratinocytes may be involved in the pathological process in interface dermatitis.
