Mycobacterium avium pleuritis with multiple nodules in the pleura

As opposed to tuberculosis, pleurisy hardly develops in patients with nontuberculous mycobacteria (NTM) infection. In spite of increasing prevalence of NTM infection, little is known about thoracoscopic or pathological findings of the NTM-infected pleura. We now report the first case of NTM pleuritis with multiple granulomatous nodules in the pleura. A 74-year-old woman was admitted to our hospital due to massive effusion of the left thoracic cavity. The analysis of pleural fluid showed lymphocytic exudative effusions with increased levels of adenosine deaminase, although culture of the pleural fluid was negative. The patient accordingly underwent thoracoscopy, which revealed multiple pleural nodules. Biopsy of the nodules demonstrated epithelioid cell granulomas without caseous necrosis. In addition, culture of the biopsy specimens confirmed infection by Mycobacterium avium. As culture of pleural fluid often fails to detect NTM pathogens, demonstration of pleural nodules during thoracoscopy can contribute to prompt diagnosis and treatment of NTM pleuritis.