Mucocoele formation due to congenital bronchial atresia--a rare cause of solitary pulmonary nodule.

We present a case of congenital bronchial atresia with unique features in a twenty eight years old asymptomatic, non-smoker male who presented to our department for X -ray chest as a part of routine annual medical check up. It revealed an incidental, well defined, branching opacity in the left upper lobe close to the hilum. A differential diagnosis of vascular malformation and bronchocoele was given with advice to the patient to follow up after five months. A repeat x ray chest 5 months later revealed same branching character of the opacity. The CT scan of chest showed the detailed characteristics of the opacity. The lesion was located in the apico-posterior segment of the left upper lobe. It was non-enhancing and had a typical branching character with paucity of vessels in the surrounding lung. Lack of symptoms and CT features of the opacity were sufficient to label this patient as a case of congenital bronchial atresia with mucocoele formation . No frank emphysematous change had yet developed around the atretic bronchial segment.