Combined pulmonary fibrosis and emphysema

CPFE = upper-lobe predominant emphysema plus clinically significant fibrotic ILD (often UIP/IPF) with a characteristic physiology (preserved volumes but poor gas transfer) and high complication risk.

Physiology and clinical implications

• Spirometry and lung volumes can be near-normal or only mildly abnormal.
• DLCO is often disproportionately reduced (key clue).
• Pulmonary hypertension is common and drives prognosis.
• Increased lung cancer risk compared with emphysema or fibrosis alone.

Key imaging features

Radiograph

Hyperinflation plus basal reticulation. Lung volumes may look less reduced than expected for the amount of fibrosis.

HRCT

• Emphysema: centrilobular and/or paraseptal, classically upper lobes.
• Fibrosis: commonly UIP pattern in lower lobes (subpleural reticulation, traction bronchiectasis, honeycombing).
• “CPFE feel”: relatively preserved lung volumes despite extensive fibrosis.

Pitfall

Paraseptal emphysema cysts can mimic honeycombing. True honeycombing usually comes with other fibrotic signs (traction bronchiectasis, architectural distortion) and stacked subpleural cysts with shared walls.

Top differentials

• Emphysema with mild basal scarring or dependent atelectasis: fibrosis not extensive, limited architectural distortion.
• Fibrotic hypersensitivity pneumonitis with emphysema: air-trapping, mosaic attenuation, distribution not classic basal-subpleural UIP.
• Smoking-related ILD (RB-ILD/DIP) with emphysema: more ground-glass than architectural distortion, less definite UIP morphology.