Cystic Lung Disease

Abstract

A lung cyst is a round parenchymal lucency or low-attenuating area with a well-defined interface with adjacent normal lung and surrounded by an epithelial or fibrous wall that is often less than 2 mm in thickness. Diseases that manifest with lung cysts comprise a limited but well known group of entities. Classic diseases manifesting with diffuse lung cysts include pulmonary Langerhans cell histiocytosis (PLCH), lymphangioleiomyomatosis (LAM), lymphocytic interstitial pneumonia (LIP) and Birt-Hogg-Dubé syndrome. However, it is important to recognize other conditions that may mimic cystic lung disease, such as pneumatoceles, tracheobronchial papillomatosis, cavitary disease (e.g. tuberculosis, fungal infection), bronchiectasis, and emphysema. Differentiation between true cysts and cyst mimics may be difficult, and may rely on identification of ancillary findings.