[A congenital lung cyst in a child with clinical manifestations after a 7-year latent period].

Congenital cysts of the lung originate from embryological malformation of the lung bud and usually produce clinical signs in the first months of life by expansion, causing respiratory distress, or by infection through its bronchial communication. We report a rare case of solitary congenital lung cyst in the middle lobe which was diagnosed in the 3rd month of life and remained silent until the 7th year when tension pneumothorax developed from rupture of the rapidly expanding cyst. An urgent lobectomy of the involved lobe was performed. This rare case supports the attitude that every congenital cyst of the lung should be excised as soon as the correct diagnosis is established in order to prevent serious complications.