Clinical History
A 42-year-old woman with no history of respiratory problems or other relevant diseases came to the emergency department of our hospital with complaints of coughing and auto-limited haemoptysis.
Imaging Findings
The patient underwent a chest X-ray where a well-defined lobulated opacity was seen. It was located in the apicoposterior segment of the left upper lobe and extended from the hilum to the pulmonary apex. Subsequently, a chest CT with multiplanar reformations was performed, which revealed a branching lobulated mass with homogeneously low density that reminded of a mucoid impaction in the apicoposterior segment of the left upper lobe.
The CT showed a lack of communication between the mass and the hilum as well as hypoattenuating lung, air trapping and focal parenchyma oligaemia surrounding the mass. A bronchocele caused by congenital bronchial atresia was diagnosed, but the patient underwent a bronchoscopy and a PET-CT to rule out a tumoral origin. Both were normal.
One month later, the patient underwent a follow-up chest X-ray that revealed the decreased size of the mass, an additional finding that is consistent with the CT diagnosis of bronchocele.
Discussion
A bronchocele is a dilated bronchus with mucus impactation at the proximate of an atretic or obstructed bronchus. The cause of bronchocele formation can be either obstructive (bronchial atresia, neoplasia, intrapulmonary bronchogenic cyst, intralobar sequestration, broncholithiasis, tuberculous stricture…) or non-obstructive (asthma, ABPA or cystic fibrosis) [1]. From all of them, congenital bronchial atresia is the most common cause of bronchocele and the apicoposterior segment of the left upper lobe is the most common location of this entity, as it happened in our case [2].
Bronchial atresia is a rare variety of chest anomaly. It generally results from a localized defect in normal broncho-pulmonary embryogenesis.
Even though the patients are usually asymptomatic, they may also suffer from symptoms such as dyspnoea, cough, recurrent pneumonia and haemoptysis [3, 4].
Bronchocele can be diagnosed radiologically or by bronchoscopy. Bronchoscopically, stenosis may be demonstrated at the atretic bronchus yet it may be normal as well [3], as in our case, which is why radiological images are imperative. Bronchoscopy and PET/CT are also recommended for patients with bronchial atresia in order to exclude other possible pathologies, such as tumoral masses (there is no endobronchial lesion or FDG activity, as in our case). The classic findings in the chest X-ray of bronchocele caused by bronchial atresia is a lobed, branching tubular or nodular opacity that extends from the hilum with surrounding hyperlucent lung parenchyma. In the CT, bronchocele is seen as a lobed hypodense mass with lack of communication with the hilum. CT is the most sensitive imaging modality, and when findings are typical, as in our case, it provides the diagnosis [2, 3]. In an estimated 20% of cases, segmental bronchial atresia causes recurrent infection, which is manifested radiologically as consolidation and, occasionally, as an enlarging nodule or mass that varies in size over the course of time [5].
The treatment of this entity depends on the symptoms. Asymptomatic patients don't need any treatment but surgical excision may be required for patients with complications secondary to the atretic bronchus [2].
Differential Diagnosis List
Bronchocele caused by a congenital bronchial atresia
Tumoral masses
Congenital abnormalities (congenital cystic adenomatoid malformation
pulmonary sequestration
bronchogenic cyst)
Bronchiectasis in asthma
ABPA and cystic fibrosis
Final Diagnosis
Bronchocele caused by a congenital bronchial atresia