Table 1 Histological and clinical classification of idiopathic interstitial pneumonias*.

Histological patterns	Clinical/radiological/pathological diagnosis
Usual interstitial pneumonia	Idiopathic pulmonary fibrosis/cryptogenic fibrosing alveolitis
Non‐specific interstitial pneumonia	Non‐specific interstitial pneumonia (provisional)†
Organising pneumonia	Cryptogenic organising pneumonia‡
Diffuse alveolar damage	Acute interstitial pneumonia
Respiratory bronchiolitis	Respiratory bronchiolitis interstitial lung disease
Desquamative interstitial pneumonia	Desquamative interstitial pneumonia
Lymphoid interstitial pneumonia	Lymphoid interstitial pneumonia

*Unclassifiable interstitial pneumonia: some cases are unclassifiable for a variety of reasons.

†A heterogeneous group with poorly characterised clinical and radiological features that needs further study.

‡Cryptogenic organising pneumonia is the preferred term but it is synonymous with idiopathic bronchiolitis obliterans organising pneumonia.

Reproduced with permission from the American Thoracic Society/European Respiratory Society.¹