Is There a Relationship Between Paratracheal Air Cysts and Upper Lobe Fibrosis?

Abstract

Paratracheal air cysts are relatively common, but the etiology is still unclear. We detected increased rates of cyst formation that may result from the traction effect on the tracheal wall in the presence of upper lobe fibrosis.

Incidental Paratracheal Air Cysts on Thoracic CT and Their Association with Chronic Inflammatory Lung Disease

“…In a recent study, it was proposed that upper lung fibrosis could cause traction of the tracheal wall and result in cyst formation [4]. We also considered that upper lung fibrosis might be associated with both development and morphologic changes of PACs.…”

“…Paratracheal air cysts (PACs) are small air collections and are usually detected incidentally by thoracic computed tomography (CT) [1–4]. The incidence of PACs in the general population has been reported to be from 0.75% to 8.1% [3, 5–7].…”

“…Most PACs are asymptomatic, but rarely, they are the cause of recurrent infections, chronic cough, right side recurrent laryngeal nerve paralysis, and difficult intubation [3, 4, 7]. PACs are usually located on the right side of tracheal area at the level of the thoracic inlet [2, 4, 6, 8].…”

“…PACs are usually located on the right side of tracheal area at the level of the thoracic inlet [2, 4, 6, 8]. Histological findings show that PACs are lined with ciliated columnar epithelia and often communicate with tracheal lumen [5, 6].…”

“…PACs and tracheal diverticula are considered similar entities [5]. Tracheal diverticula develop by mucosal herniation through weak points in the trachea due to increased intrathoracic pressure [1, 4, 5]. …”