Tuberculosis of skeletal muscle in a case of polymyositis.

We describe a patient with polymyositis receiving corticosteroid therapy, who presented with persistent fever and mass lesion at the left thigh. Surgical exploration and mycobacterial culture proved to be Mycobacterium Tuberculosis infection involving the semitendinous muscle of the left thigh. Suitable surgical debridement, anti-TB medications, and sufficient corticosteroid administration resulted in a good control of both polymyositis and the tuberculous infection.