A 76-year-old woman with muscle ache, weakness of the extremities, and skin rash was diagnosed with dermatomyositis (DM). Upon the diagnosis of DM, a systemic survey of malignancy revealed an advanced carcinoma of the ascending colon. The patient underwent right hemicolectomy approximately 2 months after the onset of DM. The symptoms and signs of DM disappeared after the surgery without additional therapy. DM is an idiopathic systemic inflammatory disease characterized by muscle ache, muscle weakness, and skin rash. In some cases, DM develops as paraneoplastic syndrome, and it is assumed that 30% of DM patients have cancer. Symptoms and signs of DM can be attenuated by treatment of the malignancy, and they reappear if the malignancy recurs. It is essential to perform a systemic survey of malignancy in DM patients, and treatment of the malignancy has to precede treatment of DM.
Keywords: Colon cancer; Dermatomyositis; Paraneoplastic syndrome; Polymyositis.