Honeycombing refers to the computed tomographic (CT) manifestation of diffuse pulmonary fibrosis (usual interstitial pneumonia). CT demonstrates clustered cystic air spaces (between 0.3-1.0 cm in diameter), which are usually subpleural and basal in distribution. The walls of the cysts are well-defined and often thick (1-3 mm 4). Honeycombing is an irreversible finding in interstitial lung disease and associated with a poor prognosis.
Honeycombing consists of enlarged airspaces with thick fibrotic wall lined by bronchiolar epithelium and often filled with mucin and inflammatory cells 6.
- air-space consolidation in the presence of pulmonary emphysema can mimic this appearance.
- in some situations, paraseptal emphysema and paracicatrical emphysema can also mimic honeycombing 3
The term “honeycomb lung” is thought to have originated in the 19th century in Germany and is thought to have first appeared in 1949 in a study by N Oswald and T Parkinson 5.