Congenital aerodigestive fistula with extraordinarily delayed adult presentation: a case report and review of endoscopic closure for bronchoesophageal fistula.

Background: Congenital aerodigestive fistulae (ADF) represent extremely rare developmental malformations derived from disrupted embryological separation of the primitive foregut, which can be classified by lesion location into tracheoesophageal fistulae, bronchoesophageal fistulae (BEF), and other subtypes. While typically diagnosed in neonates, isolated BEF without esophageal atresia ("H-type") may remain undetected for decades, presenting in adulthood with chronic, stereotyped symptoms. Endoscopic interventions for congenital BEF remain poorly characterized, with limited evidence regarding patient selection and technique optimization. Case presentation: A 58-year-old man presented with a 40-year history of persistent, swallowing-induced cough, accompanied by expectoration of white mucoid sputum. Initial chest computed tomography at an outside hospital identified a left lower lobe mass suspicious of lung cancer complicated by obstructive pneumonia. Bronchoscopy confirmed an esophageal-left main bronchial fistula, and endobronchial ultrasound-guided biopsy demonstrated acute and chronic inflammation with fibrous hyperplasia. Repeat imaging at our institution demonstrated a direct, upward fistulous tract between the mid-esophagus and left main bronchus, consistent with Braimbridge and Keith Type II congenital BEF. A multidisciplinary consensus deemed surgical repair high-risk with uncertain efficacy, and the patient declined operative intervention. Combined bronchoscopy and esophagoscopy under general anesthesia confirmed a 2-mm fistula orifice 2 cm below the left main carina. The fistula was successfully closed using argon plasma coagulation-mediated de-epithelialization followed by over-the-scope clip (OTSC) deployment, with immediate resolution of swallowing-induced cough. At the 10-month follow-up, esophagography showed no contrast extravasation, computed tomography confirmed no persistent fistulous communication, and esophagoscopy demonstrated granulation tissue with white scarring and no identifiable fistula orifice. Conclusion: This case illustrates the potential for extraordinarily delayed presentation of congenital BEF in adulthood and highlights the importance of maintaining a high index of suspicion for this rare anomaly in patients with chronic, liquid-induced paroxysmal cough. Combined endoscopic de-epithelialization and OTSC closure appears to be an effective, minimally invasive alternative to surgical repair in eligible patients with congenital BEF. More clinical studies are warranted to develop consensus-based guidelines for the management of benign ADF.