A solitary pulmonary nodule caused by Mycobacterium avium with pleural effusion and pleuritis after transbronchial biopsy: a case report

Background: Pleural effusion and pleuritis are uncommon manifestations of Mycobacterium avium complex pulmonary disease. Pleuritis caused by Mycobacterium avium complex pulmonary disease presenting as a solitary pulmonary nodule is extremely rare. The pathogenesis of Mycobacterium avium complex pleuritis has not been elucidated. However, it has been suggested that secondary spontaneous pneumothorax from Mycobacterium avium complex pulmonary disease is one of the causes of Mycobacterium avium complex pleuritis. Case presentation: A 67-year-old Japanese woman who presented with a solitary pulmonary nodule developed a transient pneumothorax after transbronchial biopsy. A definitive diagnosis of solitary pulmonary nodule could not be made on bronchoscopy, so video-assisted thoracoscopic surgery was performed 1 month after bronchoscopy. On the day of hospitalization for the procedure, a left-sided pleural effusion appeared on a chest radiograph. Thickening of the parietal and visceral pleura and numerous scattered white small granules were seen on thoracoscopy. Histologic examination of the resected left lower lobe and a biopsy of the parietal pleura showed Mycobacterium avium complex solitary pulmonary nodule and Mycobacterium avium complex pleuritis. Conclusion: Iatrogenic pneumothorax can be a cause of pleuritis in a patient with Mycobacterium avium complex pulmonary disease. Clinicians should watch for the appearance of secondary pleuritis after transbronchial biopsy even in a patient with localized disease such as Mycobacterium avium complex solitary pulmonary nodule.