Infectious Etiologies of Diffuse Cystic Lung Diseases

Lung cysts are defined as low-attenuating, gas- or liquid-containing circumscribed spaces within the lung parenchyma that are enclosed by an epithelial or fibrous wall that forms a well-defined interface with the normal lung tissue. A limited number of infectious agents produce cystic lesions in the lung that can mimic the more common diffuse cystic lung diseases (DCLDs) seen in pulmonary clinics. The clinical history and acuity of illness often distinguish these disorders from the more indolent chronic DCLDs. This review describes infectious etiologies of cystic lung disease as well as the mechanisms of cyst development, the clinical and radiographic presentations, and the clinical management, with a special focus on the prototypical DCLD-associated infection, Pneumocystis jirovecii.