Anti-MDA5 Antibody-Positive Clinically Amyopathic Dermatomyositis Associated With Multiple Heterologous Carcinomas: A Case Report.

Dermatomyositis (DM), an autoimmune disorder, is linked to increased malignancy risk. A 53-year-old man with anti-melanoma differentiation-associated gene 5 (MDA5)-positive clinically amyopathic dermatomyositis (CADM) and rapidly progressing interstitial lung disease (RP-ILD) developed heterochronous gastric and colorectal cancers. Early endoscopic screenings led to successful curative resections, preventing recurrence. Despite low cancer incidence assumptions in patients with anti-MDA5-positive RP-ILD, this case advocates for reevaluation and periodic cancer screenings to enhance management, considering the improved survival with intensive therapy. Vigilance for multiple carcinomas at various time points is vital in CADM management.