Empyema necessitatis due to methicillin-resistant Staphylococcus aureus: case report and review of the literature

Empyema necessitatis is a rare complication of empyema in which the pleural infection spreads outside of the pleural space to involve the soft tissues of the chest wall. Most cases of empyema necessitatis are related to Mycobacterium tuberculosis and, less commonly, to Actinomyces spp. and Streptococcus spp. Staphylococcus aureus has rarely been reported as the causative agent of empyema necessitatis, with the majority of S. aureus isolates being methicillin sensitive. Only two cases of empyema necessitatis due to methicillin-resistant S. aureus (MRSA) have been reported in the medical literature. We report the case of a 59-year-old Caucasian male who presented to our institution with complaints of pain in and swelling of his left upper chest of 2-months duration. A computed tomography scan of the chest showed an 8.1- by 6.5-cm lesion which extended from the left upper lobe of the lung into the extrathoracic soft tissues beneath the left upper pectoralis muscle. A wedge resection of the left upper lung lobe revealed lung tissue with an organized pneumonia-like pattern associated with marked acute pleuritis. Blood and urine cultures and cultures of the left chest soft tissue mass grew MRSA. The patient was successfully treated with vancomycin followed by a 10-day outpatient course of ciprofloxacin and trimethoprim-sulfamethoxazole. This case represents an extremely rare manifestation of an increasingly dangerous bacterial pathogen.