Background: Dermatomyositis is an idiopathic inflammatory myopathy with an incidence of 1 in 100,000. Clinically, it features typical skin abnormalities and muscle weakness. In a subset of cases an underlying malignancy may be present; in such instances the term paraneoplastic syndrome is used.
Case description: We saw a 75-year-old male with progressive skin abnormalities, especially on the chest and hands. In addition, he experienced weakness in his arms and legs. Three months earlier, he was diagnosed with prostate cancer. Following additional investigations, the diagnosis of dermatomyositis was made and treatment with prednisone proved successful.
Conclusion: In a patient with typical skin abnormalities one should consider dermatomyositis and it is important to investigate for the presence of muscle disorders and occult malignancy. The muscle symptoms often respond well to prednisone, but the skin abnormalities are usually harder to resolve, Treatment of a possible underlying malignancy also influences the dermatomyositis.