Table 1 Radiologic and histopathologic features suggestive of a fibrotic lung disease other than IPF

Radiologic features

Areas of decreased attenuation

Bronchiectasis far from fibrotic areas

Plaques and/or significant pleural thickening

Fibrosis, linear opacities and traction bronchiectasis predominantly in the perihilar regions and upper lobes

Centrilobular nodules Mid-upper lobe predominance

Signs of pulmonary hypertension disproportionate to the extent of fibrosis

Limited extent

Conglomerate masses of fibrosis in the posterior part of the lungs

Pleural or pericardial effusion Oesophagus or bone abnormalities

Small well-defined nodules with a perilymphatic distribution

Histological features

Cellular interstitial pneumonia

Dense perivascular collagen

Pleural abnormalities

Non-caseating granulomas with a characteristic perilymphatic distribution

Multinucleated giant cells or granulomas situated around bronchioles

Extensive pleuritis

Asbestos bodies

Lymphoid aggregates with germinal center formation

Bronchial wall fibrosis

Prominent plasmacytic infiltration

Fibroblastic foci infrequent