Tuberculous infection of skeletal muscle in a case of dermatomyositis.

A patient with dermatomyositis associated with carcinoma was treated with steroids and antibiotics for possible tuberculosis. Autopsy showed an overwhelming diffuse nongranulomatous infection of Mycobacterium tuberculosis involving only the skeletal muscles and one inguinal lymph node. The rare localization of tuberculosis to skeletal muscle in this case is possibly due to steroid immunosuppression and the humoral immune attack on muscle blood vessels that is a part of dermatomyositis.