Empyema necessitans caused by Mycobacterium tuberculosis in an immunocompetent patient.

A 22-year-old man, a recent immigrant from Mexico, was admitted to a Wisconsin hospital because of a swelling of the chest wall and right axilla. Originally, it was thought to be a skin infection with Staphylococcus aureus. When the treatment was unsuccessful, the patient returned to the hospital and the abscesses were found to have been caused by Mycobacterium tuberculosis. Furthermore, there were pleural collections and it was thought that he had a manifestation called empyema necessitans, an extension of purulent pleural liquid through adjacent tissues to form an abscess on the thoracic wall.