A swollen leg: Disseminated tuberculous pyomyositis after treatment of miliary tuberculosis in an immunocompromised patient

We report a patient with a rheumatic overlap syndrome on hydroxychloroquine and prednisone who developed tuberculous pyomyositis shortly after receiving 9 months of treatment of miliary tuberculosis. Her only presenting symptom was swelling of the left lower extremity without any systemic manifestation, despite extensive radiographic evidence of disseminated abscess formation. Acid-fast bacilli stains and cultures of the purulent material were negative for Mycobacterium tuberculosis (MTB), but polymerase chain reaction confirmed the diagnosis. To our knowledge, this is the first case report of tuberculous pyomyositis that developed shortly after the patient completed a full course of antituberculous therapy. We believe that the concurrent therapy of her rheumatic overlap syndrome with hydroxychloroquine likely led to her treatment failure for MTB and will discuss the possible pathogenesis. Our case also illustrates that MTB can cause significant soft tissue disease without systemic manifestations and that polymerase chain reaction is a valuable diagnostic study.