A 43-year-old man was referred to our clinic after an incidental finding of a fistulous opening at the lower third of the esophagus on esophagogastroduodenoscopy that was conducted during routine health screening (Fig. 1A). He had no significant medical or surgical history, but had reported a chronic cough over a period of 20 years. His physical exam and results of laboratory tests were unremarkable.

Our clinical impression was of an abnormal communication between the airway and esophagus. We first performed chest radiograph and CT. The chest radiograph was unremarkable. On CT we observed an outpouching sac, which had thin enhancing walls contiguous with the mucosal layer of the esophagus at the right side of the lower esophagus (Fig. 1B). This finding suggested a mucosal layering fistulous tract arising from the esophagus. Bronchial dilation with wall thickening and peripheral patchy ground glass opacities were noted in the superior segment of the right lower lobe on CT with lung window settings (Fig. 1C), and such findings can represent chronic and recurrent infection. There was no evidence of malignancy or lymphadenopathy around the fistulous tract on chest CT. We performed barium esophagography for further evaluation of communication between the esophagus and airway, which confirmed BEF between the lower esophagus and the right lower lobe superior bronchus (Fig. 1D). We decided to perform surgical treatment to prevent secondary complications such as recurrent pneumonia or abscess. The fistula identified was identified using video-assisted thoracoscopic surgery (VATS) and was 1 cm in diameter (Fig. 1E). The fistulous tract was divided, and each end was closed using surgical staples. No remnant fistula was noted on follow-up barium esophagography after surgery (Fig. 1F). The patient was discharged from the hospital without any complications. After 3 months, follow up CT showed improvement of the inflammatory changes in the superior segment of the right lower lobe and no evidence of any complications (Figs. 1G and 1H).

Congenital BEF, originally described by Braimbridge and Keith,1 results from failed tracheoesophageal separation in the early stages of embryonic development. The congenital nature of such fistulae is characterized by the absence of adherent lymph nodes and surrounding inflammation,5 by the presence of mucosa and definitive muscularis mucosa within the fistulous tract,4 and by the onset of symptoms in childhood.1 In our case, we could not obtain pathologic results of the fistula tract through surgical treatment. However, our patient reported experiencing chronic coughing since childhood and we observed suspicious findings of the mucosal layer within the fistulous tract on CT. Therefore, we diagnosed our patient with congenital BEF. Although there were inflammatory changes around the fistulous tract on CT, we regarded these findings to represent secondary infection due to congenital esophagobronchial fistula. Moreover, some reports of congenital BEF also revealed chronic inflammatory changes around fistula tracts on CT.67

Patients with BEF may have nonspecific signs over long periods of time, such as vague thoracic or epigastric pain, heart burn, mild dysphagia, weight loss, and recurrent pulmonary infections.5 Coughing after liquid ingestion (Ohno's sign) is a more specific sign, frequently associated with productive sputum, fever, and hemoptysis.5 The duration of symptoms varies from 6 months to 50 years before diagnosis.3458 Usually symptoms depend on fistula size, being more evident in short, wide communications and more discreet in narrow fistulae. Such fistulae may become life threatening, with repeated infections leading to pneumonia, bronchiectasis, and abscess formation.49

Theories to explain the delay in onset of symptoms include the presence of a membrane, which subsequently ruptures, an occluding proximal fold of esophageal mucosa (flap valve) that becomes less mobile and occlusive with age, and a fistulous tract running upward from the esophagus to the bronchus that may close during swallowing.1

Barium esophagography usually aids diagnosis and is the initial study of choice. Esophagoscopy and bronchoscopy may not always demonstrate the fistulous orifice.5 CT may demonstrate fistulous tracts between the esophagus and airway, but is usually not confirmative.3 CT can show consolidation, ground glass opacity, masses, or bronchial dilation; these findings represent chronic and recurrent infection, secondary to esophagobronchial fistula. CT is utilized to rule out neoplasm or lymphadenopathy and to define the extent of coexisting pulmonary disease, which may require resection.34

Once BEF is confirmed, early surgical intervention is considered definitive and results in successful outcomes. Surgical approaches can be divided into two main approaches: division of the fistulous tract, and excision of the entire communication.345 In our case, the fistulous tract was divided and each opening was closed. Additional pulmonary resection is often needed in patients with coexistent pulmonary disease. Some authors have suggested endoscopic and even medical treatment methods to avoid invasive surgical treatment.10

Congenital BEF is a rare anomaly in adults with insidious and inconspicuous symptoms, which require a high degree of suspicion for successful diagnosis. Congenital BEF should be considered in the diagnosis of adult patients with suspicious abnormal communications between the esophagus and bronchus without evidence of malignancy or lymphadenopathy around the fistulous tract on chest CT. In these patients, barium esophagography is useful for confirming the presence of the fistula tract and consequently this rare diagnosis.