Tuberculous myositis is extremely rare, even in immunocompromised hosts. We present a case of disseminated tuberculous myositis in a girl with secondary acute myelogenous Leukemia following successful chemotherapy for undifferentiated sarcoma of the maxillary sinus. The diagnosis was established by direct visualization of acid-fast bacilli in the biopsied nodule and by typical pathologic findings. Three weeks after initiation of antituberculosis treatment, the patient experienced both clinical and radiologic improvement.