Tracheal Diverculum: A Rare Entity Diagnosed in the Context of Blunt Thoracic Trauma Report of A Case

Abstract

Tracheal diverticulum (TD) is an outpouching or sac arising from the wall of the trachea. It can can be classified, based on etiology, in congenital and acquired. Congenital tracheal diverticulum is the consequence of a defect in endodermal differentiation of the membranous posterior tracheal wall and it contains all the layers of the airway wall (true diverticulum). Acquired diverticulum is the result of an abnormally increased pressure inside the airways pushing the respiratory mucosa out of a defect of the airway wall; it contains only mucosa (pseudodiverticulum). Both types are rare, accounting only for a limited percentage of the paratracheal air cysts (PTACs) from which TD should be differentiated in consideration of the similar basic pattern of “paratracheal air collection”. Diagnosis of TD is difficult because of its rarity, lack of symptomatology or specific symptomatology and low sensibility of the diagnostic tools available to date (chest CT and bronchoscopy). Apart from its intrinsic rarity, the case of TD we present here has the peculiarity of being diagnosed, differently from usual, by direct bronchoscopic visualization. The blunt thoracic trauma of which the patient was victim, gives more exemplarity to the diagnostic pathway of this entity. Indeed the detection of a para tracheal air collection on CT images could have been interpreted as a traumatic rupture of the trachea rather than a TD, leading to an unjustified surgical treatment. It was only clinical judgment combined with the use of the diagnostic imaging and bronchoscopy that conducted to the correct diagnosis.