Enlarged mediastinal air cyst in a patient with bronchial diverticula localized in the left main bronchus: a case report with surgical and bronchoscopic findings

Abstract

BackgroundA mediastinal air cyst is a rare computed tomography (CT) finding. Once the lesion is identified, it is difficult to diagnose and treat. Meanwhile, bronchial diverticula have been reported as a CT finding observed in certain pulmonary pathologic conditions. We encountered the case of an enlarged mediastinal air cyst accompanied with bronchial diverticula and upper lobe-dominant fibrous changes of the lung.Case presentationA 69-year-old man with a chronic cough who had regularly visited a chest physician for upper lobe-dominant pulmonary fibrosis was referred to our hospital for the examination of an enlarged mediastinal air cyst. Chest CT exhibited an air cyst (size, 30 mm) connected to the lumen of the left main bronchus (LMB) and multiple tiny outpouches only on the LMB. Flexible bronchoscopy showed bubbling from slits or indentations of the bronchial mucosa only in the LMB but not in the right main bronchus or lobar bronchus. For therapeutic diagnosis, we removed the air cyst. Based on clinical, surgical, and pathological findings, we diagnosed the air cyst as an enlarged bronchial diverticulum.ConclusionsThis is the first case wherein bronchoscopic and surgical findings of bronchial diverticula and an enlarged bronchial diverticulum are reported. There are possible pathogenic mechanisms in cases of pulmonary disease that are attributable to enlargement of the bronchial diverticula.Electronic supplementary materialThe online version of this article (doi:10.1186/s40792-016-0282-y) contains supplementary material, which is available to authorized users.

Enlarged Bronchial Diverticula with Lung Fibrosis Progression

“…Most airway diverticula are located in the right posterolateral region of the trachea and are a rare disorder that is often asymptomatic and usually detected incidentally by radiography ( 1 ). Only one case of bronchial diverticulum has been reported besides our patient, and that case was also associated with Upper-PF ( 2 ). Clinicians should recognize that the mechanical traction and vulnerability in cases of Upper-PF might play a role in inducing pneumomediastinum or bronchial diverticula.…”

A case report of congenital bronchial diverticulum and bronchogenic cyst presenting with a whistle

“…Mediastinal air cysts due to bronchogenic diverticulum are extremely rare, and their differential diagnosis may include tracheocele (also known as paratracheal air cyst or tracheal diverticulum), bronchogenic cyst, and bronchopulmonary foregut duplication cyst [5].…”