Case of late diagnosis of dermatomyositis with anti-synthetic syndrome

Polymyositis (PM) and dermatomyositis (DM) are autoimmune diseases of skeletal muscles of unknown etiology, which belong to systemic diseases of the connective tissue and are collectively called «idiopathic inflammatory myopathies». The most severe subtype of polymyositis and dermatomyositis (PM/DM) is antisynthetase syndrome (ACC), associated with the presence of specific immunological markers in the blood serum – antisynthetase antibodies. ACC has clinical features that distinguish it from the PM/DM group as a whole. Interstitial lung disease, the most common extramuscular lesion in PM/DM, is a klyuchevoy prognostic factor in the course of the disease, as well as determining therapeutic tactics and prognosis. Difficulties in the timely diagnosis of DM with ACC are often associated with the fact that the disease can begin with pulmonary symptoms in the absence of obvious signs of myopathy. A clinical case of late diagnosis of this disease is presented.