Cancer-associated dermatomyositis: A scoping review of the literature

Dermatomyositis is an inflammatory muscle disease with distinctive skin changes and a strong association with cancer, but the mechanisms behind this link and predictors of malignancy remain unclear.

To summarize current evidence on the relationship between dermatomyositis and cancer, including epidemiology, clinical and serologic predictors, histopathology, and prognosis.

A comprehensive search of PubMed, Scopus, and Cochrane was performed according to PRISMA-ScR recommendations. Eligible studies were systematically screened, and relevant data were charted and descriptively summarized.

Fifty-nine studies met the criteria. Over half of cancers occurred within one year of dermatomyositis onset, and nearly 90% within three years. Genitourinary, gastrointestinal, and lung cancers were most common. Higher risk was linked to older age, male sex, dysphagia, severe skin disease, absence of interstitial lung disease, and anti-transcription intermediary factor 1-gamma or anti-nuclear matrix protein 2, while anti-Mi-2 suggested lower risk. Prognosis was significantly worse in patients with cancer.

Cancer-associated dermatomyositis is a distinct subtype, supporting early and repeated cancer screening and the need for standardized surveillance protocols.