A Stepwise Diagnostic Approach to Cystic Lung Diseases for Radiologists

Korean J Radiol. 2019 Sep;20(9):1368-1380. doi: 10.3348/kjr.2019.0057.


Lung cysts are commonly seen on computed tomography (CT), and cystic lung diseases show a wide disease spectrum. Thus, correct diagnosis of cystic lung diseases is a challenge for radiologists. As the first diagnostic step, cysts should be distinguished from cavities, bullae, pneumatocele, emphysema, honeycombing, and cystic bronchiectasis. Second, cysts can be categorized as single/localized versus multiple/diffuse. Solitary/localized cysts include incidental cysts and congenital cystic diseases. Multiple/diffuse cysts can be further categorized according to the presence or absence of associated radiologic findings. Multiple/diffuse cysts without associated findings include lymphangioleiomyomatosis and Birt-Hogg-Dubé syndrome. Multiple/diffuse cysts may be associated with ground-glass opacity or small nodules. Multiple/diffuse cysts with nodules include Langerhans cell histiocytosis, cystic metastasis, and amyloidosis. Multiple/diffuse cysts with ground-glass opacity include pneumocystis pneumonia, desquamative interstitial pneumonia, and lymphocytic interstitial pneumonia. This stepwise radiologic diagnostic approach can be helpful in reaching a correct diagnosis for various cystic lung diseases.

Keywords: Birt-Hogg-Dubé syndrome; Computed tomography; Histiocytosis; Langerhans cell; Lung diseases; Lymphangioleiomyomatosis.

Publication types

  • Review

MeSH terms

  • Amyloidosis / diagnostic imaging
  • Birt-Hogg-Dube Syndrome / diagnostic imaging
  • Cysts / diagnostic imaging
  • Diagnosis, Differential
  • Histiocytosis, Langerhans-Cell / diagnostic imaging
  • Humans
  • Lung Diseases / diagnosis*
  • Lung Diseases / diagnostic imaging
  • Lymphangioleiomyomatosis / diagnostic imaging
  • Pneumonia, Pneumocystis / diagnostic imaging
  • Tomography, X-Ray Computed / methods*

Supplementary concepts

  • Cystic Disease Of Lung