Incidental Finding of Tracheal Bronchus in a Patient With Bronchogenic Carcinoma

Abstract

INTRODUCTION:Congenital tracheobronchial anomalies are a rare occurrence, but if present, their associated conditions and complications can cause significant morbidity and mortality in children and sometimes even in adults. CASE PRESENTATION:An elderly gentleman with a history of smoking, chronic obstructive pulmonary disease and pulmonary fibrosis, had a CT scan done for lung cancer screening, which showed a cavitary lesion measuring 14 mm in diameter in the right upper lobe and multiple enlarged mediastinal lymph nodes. A follow-up PET-CT scan showed increased uptake in the lymph nodes. He then underwent bronchoscopy, endobronchial ultrasound and biopsy of the mediastinal lymph nodes, given his extensive smoking history and concern for malignancy. Bronchoscopy findings: The main carina had a small opening present, that when entered led to a "blind pouch" with areas where 2 bronchi showed divided off but were sealed. Area resembled a "second carina". DISCUSSION:The prevalence of congenital bronchial branching anomalies, often referred to as the tracheal bronchus is approximately 0.1-2% in the general population (Chassagnon et al., 2016). Types 1 and 2 of the tracheal bronchus arise more than 2 cm from the carina, with and without narrowing of the distal trachea respectively, whereas type 3 tracheal bronchus arises less than 2 cm from the carina (Jamil & Soos, 2020). Commonly referred to as the pig bronchus, the tracheal bronchus almost always arises from the right upper lobe (Setty & Michaels, 2000). This patient's tracheal bronchus was a supernumerary bronchus that ended as two blind bronchi or a tracheal divertica, while his right upper lobe bronchus had a normal trifurcation. CONCLUSIONS:Often associated with tracheal bronchus are other congenital malformations such as congenital heart disease, VACTERL (vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula, renal anomalies, and limb anomalies), and other airway malformations (Chassagnon et al., 2016). Most patients are asymptomatic and I incidentally diagnosed on bronchoscopy, but given the variability in the origin extent of the bronchus, symptoms can include recurrent aspiration pneumonia, atelectasis, or respiratory failure. Based on symptomatology, management varies from observant watching, symptomatic management, to surgical treatment.