**4.3.4 Cysts**

Cysts are air spaces lined by epithelium, which usually have the characteristics of bronchial epithelium., They are classically known as intrapulmonary bronchogenic cysts and usually occur near the tracheal bifurcation, but they may be seen more peripherally in the lung parenchyma(Reed & Sobonya,1974;Rogers & Osmer,1964 as cited in Shapiro SD,2010).
