[Lung sequestration; a rare congenital lung disorder].

Pulmonary sequestration is a rare congenital malformation. It is characterized by an abnormal arterial supply and venous drainage and a part of the lung which is not taking part in ventilation. Asymptomatic cases have been reported, but 37% of intralobar and 60% of extralobar sequesters became symptomatic before the age of ten years and need to be removed surgically. In this article one case-report illustrates the clinical course described in most cases whilst the other describes a patient in which the course mimicked an 'untreatable' bronchiolitis.