Tracheocele, also called aerocele, tracheal hernia, tracheal diverticulum or tracheal goiter is a rare pathology 1. We report through this literature review the case of an infant in whom the diagnosis of tracheocele was evoked incidentally thanks to cross-sectional imaging by computed tomography.
A two-month-old infant who has had for a month, according to the parents, respiratory discomfort, type of inspiratory stridor peeling during crying, accompanied by a dry cough and feeding difficulties with notions of intermittent vomiting at the beginning of symptoms. This picture was the subject of a consultation and hospitalization for 10 days in the pediatric department of the mother and child hospital of the CHU MOHAMED VI, during which a suspicion of laryngomalacia would have been evoked. Imaging by cervicothoracic computed tomography without injection of contrast medium was performed. The cross-sectional CT images of the cervicothoracic region (Figure 1) and the 3D reconstruction (Figure 2) highlight a right latero- postero-tracheal airy formation opposite C7, one-eyed measuring 5.3 mm communicating with the trachea through a defect measuring 2.6 mm, which suggested the diagnosis of a right tracheocele. At the thoracic level, there were foci of condensation of the ventral segment of LSD and dorso basal segments of the two lower lobes site of aerial bronchogramma. Medical treatment was initiated, and surgical correction was considered remotely.
The tracheocele was first described by Rokitansky in 1846, and then by MacKinnon on 10 cases of incidental post-mortem discovery on autopsies 1. According to a recent review of the literature, its incidence is 1 to 2% 2. It is characterized histologically by a dehiscence of the tracheal mucosa that can be congenital or acquired and its frequency underestimated because asymptomatic and well tolerated when symptomatic 1,2. When congenital, it is usually associated with small tracheal openings. However, the acquired tracheocele has a wide tracheal communication and the traumatic context, by high-pressure injury, or long-term tracheostomy is the most frequently found etiological factor 3. In addition to trauma, recurrent infections are also an etiological factor of acquired tracheoceles 4. According to these data from the literature, our patient should be considered as having a congenital tracheocele as evidenced by the size of the defect and the absence of any notion of traumatic or other etiology found.
In all cases, when symptomatic it can occasionally manifest as chronic cough, stridor, dyspnea or recurrent infection due to the accumulation of tracheobronchial secretions in the diverticular sac 4,5. This clinical picture in infants may erroneously suggest a laryngocele, pharyngocele, vascular anomaly or other pathological entities 5. The positive diagnosis of this rare nosological entity is radiological and imaging by cervico-thoracic computed tomography occupies a place of choice by objectifying the presence of one or more latero-tracheal airy cavities communicating with the trachea through a defect, without mass effect on the trachea 5, as in the case of our patient.
Other medical imaging techniques can be used such as standard chest radiography or opacification tracheo-bronchogram that can reveal for the first a latero-tracheal clarity communicating with the rest of the trachea and for the second an addition image with sequestration of the contrast medium at the late time 6 . Other invasive non-radiological techniques such as bronchoscopy also help in diagnosis by visualizing the defect of the tracheocele and or air bubbles and secretions exiting through the defect located most often at the level of the lateral wall of the trachea 6,7.
This entity deserves to be known and reported in the radiological report with regard to the risks incurred by the patient during endotracheal intubation that may be responsible for perforation and occurrence of pneumomediastinum. Whatever its exact nature, tracheocele can be complicated by clinical signs, which may warrant surgical removal 7,8.
This case highlights the importance of medical imaging more particularly computed tomography in the diagnosis of this rare nosological entity that can be useful for the resuscitator and in the surgical approach, when an excision is to be considered.