Table 1

Categorisation and features of diffuse cystic lung diseases5 7 8

Clinical featuresCharacteristic CT findings
Cystic lesions primarily of the lung
Light-chain derived (AL) pulmonary amyloidosisAssociated with blood dyscrasias and lymphoproliferative disordersCysts of diverse sizes and shapes; seen more commonly with septal thickening, irregular nodularity and tracheobronchial lesions
LAMAssociated with pneumothorax, chylous effusions/ascites, renal angiomyolipomas and/or tuberous sclerosis complexRound, uniform cysts intermittently dispersed throughout normal lung parenchyma
Langerhans cell histiocytosisAlmost exclusively in smokersAssociated with centrilobular nodules; classically spares costophrenic angle
Sporadic cystic lung diseaseAssociated with small airways disease, hypothesised to be a consequence of chronic small airway injuryCysts of diverse sizes and shapes; associated with evidence of bronchiolitis
Follicular bronchiolitisThought to be on similar pathological spectrums, follicular bronchiolitis and LIP are almost clinically indistinguishable; can be associated with connective tissue diseasesCysts of diverse sizes and shapes; associated peribronchial distribution with parenchymal nodularity and tree-in-bud like appearances
LIPCysts of diverse sizes and shapes; associated with perivascular distribution and ground-glass opacities
Cystic lesions secondary to other diseases
Serum amyloid A (AA) pulmonary amyloidosisGenerally well tolerated and associated with diseases of chronic inflammationSimilar to primary pulmonary amyloidosis
Cystic metastasisReported in a diversity of cancers including colon cancer, bladder cancer, sarcoma and stromal tumoursCysts of diverse sizes and shapes; cysts can be filled with either fluid or air
HIVMost profound in patients who smoke; unclear relation to infectionsLarge, irregularly shaped cysts with emphysematous appearances
Cystic lesions with genetic origins
Tuberous sclerosis complexLinked to mutations in the TSC1 or TSC2 geneRadiographically similar to LAM
Birt-Hogg-Dubé syndromeLinked to mutations in the FLCN gene; familial history of pneumothoraxIrregularly sized and shaped cysts; typically subpleural most predominant in lower lobes
Cystic fibrosisLinked to mutations to the CFTR gene; associated with recurrent pulmonary infections, pancreatic insufficiency and nutritional deficienciesCysts of varying sizes favouring central, apical presentations associated with bronchiectasis
  • HIV, human immunodeficiency virus; LAM, lymphangioleiomyomatosis; LIP, lymphocytic interstitial pneumonia.