Clinical significance of para-carinal air cysts in patients with pleuroparenchymal fibroelastosis: The relationship with pneumomediastinum and pneumothorax.

Background: Para-tracheal or para-carinal air cysts (PACs) are often asymptomatic and usually detected incidentally by methods such as computed tomography. Their clinical significance is unclear in patients with pleuroparenchymal fibroelastosis (PPFE).

Methods: We evaluated the clinical significance of PACs in PPFE and their relationship with pneumomediastinum or pneumothorax.

Results: In total, 50 patients had PPFE and 34 (68%) had PACs. Most PACs were para-carinal (n = 30). A para-tracheal air cyst was detected in only nine patients, which included five patients having both para-carinal and para-tracheal air cysts. Overall median survival was 24.7 months. Survival was not significantly different between the patients with [PACs(+)] and without PACs (P = 0.268). A high frequency (64%) of the complication of pneumomediastinum or pneumothorax occurred in the overall population during follow-up. Pneumomediastinum/pneumothorax occurred significantly more frequently in patients with PACs(+) than in those without (76.5% vs. 37.5%; P = 0.012). PACs(+) was the only significant risk factor for pneumomediastinum/pneumothorax.

Conclusions: Our data showed that PACs commonly occur in patients with PPFE, and most PACs were para-carinal air cysts. Additionally, PACs(+) was a significant risk factor for pneumomediastinum/pneumothorax; therefore, clinicians should be more aware of these complications during follow-up examination, particular in PACs(+) patients with PPFE.