Paraneoplastic dermatomyositis heralded disease progression after first-line chemotherapy; however, in hindsight, subtle cutaneous features were present at sarcoma diagnosis. The temporal relationship between paraneoplastic dermatomyositis and metastatic leiomyosarcoma is key in this case, as fluctuations in dermatomyositis severity correlated with growth of metastatic disease. Understanding this relationship may provide clues for tumour progression and prompt timely initiation of anti-cancer therapy. It is important to recognise that in addition to the more common cancers associated with paraneoplastic dermatomyositis, it can also occur in rarer tumours such as leiomyosarcoma.