Congenital cystic adenomatoid malformation (CCAM) of the lung is characterized by an excessive overgrowth of the terminal respiratory bronchioles, probably of hamartomatous origin. The absence of inflammation has generally been considered obligatory for the diagnosis of CCAM of the lung in the infantile period. Furthermore, it has been argued that chronic inflammation itself may influence the development of cystic lesions within lung parenchyma. We report a case of an 11-month-old infant with CCAM malformation of the lung type III associated with a super-impossed purulent inflammation and abscess formation. In conclusion, our case clearly demonstrates that CCAM may even in infantile period become inflamed, manifesting itself with different clinical symptoms and signs, such as respiratory distress or recurrent pneumonia.