Congenital cystic adenomatoid malformation of the left lung presenting in an adult.

Haemogram and biochemical tests were normal. Chest radiograph (postero-anterior view) showed shift of the mediastinum to the left with multiple cavities on the same side and contra-lateral compensatory hyperinflation (Figure 1). Sputum smears were negative for acid-fast bacilli on two occasions. High resolution computed tomography (HRCT) (Figure 2) showed mediastinal shift to the left and elevation of the left hemidiaphragm suggestive of volume loss in the left hemithorax. Multiple thin-walled, air-filled cavities of varying sizes were seen almost completely replacing the parenchyma of both lobes of the left lung, some