Cystic interstitial lung diseases: recognizing the common and uncommon entities.

Cystic lung diseases present a considerable diagnostic challenge because they are less frequently encountered in clinical practice and high-resolution computed tomography findings are often similar in many of these diseases. Here, we review the high-resolution computed tomography findings of cystic lung diseases and their mimics and provide a systematic approach to their diagnosis. Specific diseases that are discussed include pulmonary Langerhans cell histiocytosis, lymphangioleiomyomatosis, Birt-Hogg-Dubé syndrome, lymphocytic interstitial pneumonia, and light chain deposition disease.