Agenesis of right upper lobe of lung

Agenesis of the right upper lobe of the lung is a very uncommon congenital anomaly and may be referred to chest clinics in adulthood for an incidental finding of abnormal chest radiograph. The presentations of chest radiograph may imitate many common situations such as right upper lobe collapse presenting as an ipsilateral shifting of the mediastinum or elevation of the right hemidiaphragm due to eventration or subdiaphragmatic lesions. A chest computed tomography is considered the most conclusive examination used to diagnose lung agenesis. Three-dimensional reconstructed images can be particularly helpful in delineating abnormalities of the bronchi and associated arterial and venous structures. We describe here a young woman with allergic rhinitis and bronchial asthma since her early childhood. She was referred to our clinic for an incidental finding of abnormal chest radiograph after a school health checkup. Right upper lobe atelectasis or intra-abdominal lesions were initially suspected. After a thorough image study, she was diagnosed as a case of agenesis of the right upper lobe. Our report emphasizes the importance that a high index of suspicion and adequate image investigation are necessary to diagnose congenital lung anomalies.