RESUMEN
Dermatomyositis is characterized by progressive, symmetric, proximal muscle weakness and a nonsuppurative inflammatory myopathy of unknown etiology involving predominantly skeletal muscles. It is also characterized by typical skin lesions. Interstitial lung disease has a poor prognosis when it is associated with dermatomyositis. Organizing pneumonia is a disease in which granulation tissue fills the lumina of terminal and respiratory bronchioles and extends into the distal airspaces. The cryptogenic nature of the process is appreciated in that organizing pneumonia patterns of injury can be seen in secondary forms of the disease (secondary organizing pneumonia). Organizing pneumonia has been reported to occur in 5~10% in dermatomyositis-polymyositis patients. Anti-histidyl tRNA synthetase antibody (anti-Jo-1) is a predictive disease marker that is reported to occur in up to 70% of patients. We describe a 49-year-old male dermatomyositis patient who presented with organizing pneumonia and was found to have negative anti-Jo-1 antibody.