TRACHEAL DIVERTICULUM MIMICKING PNEUMOMEDIASTINUM IN A MIDDLE-AGED WOMAN WITH ASTHMA

Abstract

SESSION TITLE: Medical Student/Resident Imaging Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Tracheal diverticulum (DV) or paratracheal cyst is a benign disorder characterized by one or more invaginations of the tracheal wall lined by ciliated columnar epithelium. It has an incidence of 2.4% with a mean size of 4 mm (2-6 mm). The majority are localized in the right posterolateral region of the trachea between T1 and T3 (1). Tracheal DV are classified as congenital and acquired based on anatomy and histology (2). CASE PRESENTATION: A 41-year-old female with history of asthma presented with progressive exertional dyspnea for 3-4 months, mild cough, and chest tightness. No inciting events. Symptoms were associated with activity and allergen exposure and improved with rest and the use of albuterol rescue inhaler. She woke up at night about 3 times per week due to dyspnea. She reported compliance with inhaled salmeterol/fluticasone twice per day. She denied wheezing, unintentional weight loss, night sweats or hemoptysis. She had recurrent URI and lost her voice attributing it to a recent episode of laryngitis. She has prior history of smoking 1-2 cigarettes/week. Physical exam was unremarkable. Labs were normal (negative for eosinophilia) except for an elevated IgE (175 IU/ml). Pulmonary function tests performed 2 years ago were consistent with small airway disease. A chest CT without contrast showed an incidental 1 cm right lower lobe nodule, mild bronchiectasis and a 9 mm defect in the posterior aspect of the tracheal wall (7o' clock position). This finding was initially characterized as pneumomediastinum by radiologist upon presentation. Dyspnea was attributed to uncontrolled asthma and improved with proper inhaler technique. DISCUSSION: Congenital tracheal DV are more common in males, are small in diameter, and are localized 4-5 cm below the vocal cords or above the carina. They are associated with developmental defects in the tracheal cartilage. Acquired tracheal DV can arise at any level and can be single or multiple, they involve the respiratory epithelium and are usually wide-mouthed and larger in size. They occur due to persistent elevation in intraluminal pressure secondary to chronic cough combined with a weakened tracheal wall. They can also occur post-surgically or as a result of tracheomalacia (1). Tracheal DV are asymptomatic and detected incidentally by imaging. The best imaging method is a thin-section multidetector CT (MDCT) with the typical finding of a thin-walled paratracheal air sac with or without communication with the tracheal lumen (1). CONCLUSIONS: The differential diagnosis of tracheal DV includes laryngocele, Zenker's diverticulum, apical hernia, and lung bullae (1). It is important to distinguish this condition from pneumomediastinum and recognize it when common respiratory symptoms do not respond to standard care. Reference #1: Sayit AT, Elmali M, Saglam D et al. The disease of airway-tracheal diverticulum: a review of the literature. J Thorac Dis 2016;8(10): E1163-E1167 Reference #2: Chaudry I, Mutari H, Hassan E et al. Tracheal Diverticulum: A Rare Cause of Hoarseness of the Voice. Ann Thorac Surg 2014; 97: e29-31. DISCLOSURES: No relevant relationships by Benjamin Batson, source=Web Response no disclosure on file for Joshua Crane; No relevant relationships by Amr Ismail, source=Web Response No relevant relationships by Barbara Mantilla, source=Web Response No relevant relationships by Kenneth Nugent, source=Web Response No relevant relationships by Myrian Vinan Vega, source=Web Response