Reticular abnormalities - Honeycombing

The term ‘honeycombing’ is used to describe the end stage of diseases that cause diffuse fibrotic destruction, are irreversible and have a poor prognosis. If present, HRCT shows thick-walled clustered cystic air spaces (0.3-1.0 cm in diameter), which are distributed subpleurally and basally. These cysts resemble a honeycomb in cross-section. This feature is typically accompanied by other signs of fibrosis, e.g. traction bronchiectasis.2,6

For a differential diagnosis it is also important to consider pulmonary emphysema, which can mimic honeycombing.