Diffuse lung cysts

1. Universidade Federal Fluminense, Niterói, Brasil. 2. Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil. 3. Faculdade de Medicina de Petrópolis, Petrópolis, Brasil. 4. Santa Casa de Misericórdia de Porto Alegre, Porto Alegre, Brasil. 5. Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brasil. The patient basically had diffuse lung cysts on HRCT examination. Cysts are characterized by rounded areas of low attenuation in the lung parenchyma and a well-defined interface with the normal adjacent lung. They are distinguishable from pulmonary emphysema because they have no arterioles at their center and usually have an identifiable wall. The cyst wall is usually thin, but it can vary in thickness. Cysts usually contain air but occasionally contain fluid. A cystic pattern is encountered in a number of diseases, the most common being lymphangioleiomyomatosis (LAM), Langerhans cell histiocytosis, lymphocytic interstitial pneumonia (LIP), and Birt-Hogg-Dubé syndrome (BHDS). Clinically, cysts are usually asymptomatic or accompanied by dyspnea and are often discovered in routine tests or when complications, such as pneumothorax, occur.