The authors report a clinical case of a 41-years-old man with astenia and myalgias maintained for many years without an accurate diagnosis. Amyopathic dermatomyositis was diagnosed based on the presence of typical cutaneous lesions and the absence of myositis. Subsequent evidence of subclinical myositis allowed the diagnosis of hypomyophatic dermatomyositis. Finally, the diagnosis of classical dermatomyositis could be made when the patient presented elevated levels of muscle enzimes. There was a good clinical response to imunossupressor therapy and the patient remains asymptomatic. Differences in the clinical management of amyopathic, hypomyopathic and classic dermatomyositis are discussed.