Malignant erythema as a high-specificity cutaneous indicator of malignancy in adult dermatomyositis: a retrospective cohort study

Background Dermatomyositis (DM) is associated with a substantially elevated risk of malignancy, yet the cutaneous features predictive of cancer risk in adults remain insufficiently defined. Objectives This study aimed to characterize cutaneous manifestations and clinical factors associated with malignancy in adult DM, with a focus on malignant erythema. Methods This retrospective cohort study included 261 adults with DM admitted between 2016 and 2023 and followed up till June 2025. Clinical data, laboratory indicators (including creatine kinase [CK] and lactate dehydrogenase [LDH]), autoantibodies, and skin findings were systematically evaluated. The primary outcome was the occurrence of malignant tumors. Results Twenty‑six patients (10%) developed malignancy. Malignant erythema was identified in 35 patients (13.3%), among whom 14 (40%) had malignancy. Both anti-transcription intermediary factor-1 γ (anti-TIF-1 γ) antibodies and malignant erythema were independently associated with malignancy (odds ratio [OR] = 18.231, 95% confidence interval [CI] 4.568–72.756, P < 0.001; OR = 17.588, 95% CI 2.151–143.824, P = 0.007). Malignant erythema demonstrated higher specificity for tumor prediction than anti-TIF-1 γ antibodies (91.1% vs. 86%, P < 0.001), while sensitivity did not differ significantly (53.8% vs. 73.1%, P = 0.190). while. Conclusion Malignant erythema is a distinctive poikilodermatous manifestation strongly associated with malignancy in adult DM. Its high specificity suggests that malignant erythema may serve as a valuable clinical indicator for malignancy risk and a useful complement to anti-TIF-1 γ antibody testing.