[Pseudotumor in the forearm caused by focal myositis. A rare form of idiopathic inflammatory myopathy].

Focal myositis is a rare form of idiopathic inflammatory myopathy. We describe an additional case of focal myositis in a 54-years-old woman presenting as a painful pseudotumor of the left forearm. Muscle enzymes were normal but generalized electromyographic abnormalities were found. We consider that focal myositis is a heterogeneous clinical syndrome, and the cases showing only focal involvement can be different from those that evolve into polymyositis.