Can pleuropulmonary fibroelastosis (PPFE) occur secondary to underlying cavitations in the upper lobes?

Can PPFE Occur Secondary to Upper Lobe Cavitations?

No, pleuropulmonary fibroelastosis (PPFE) does not occur secondary to cavitations; rather, PPFE itself may predispose to pneumothorax and recurrent infections, which could theoretically lead to cavitary lesions as complications rather than causes.

Understanding PPFE Etiology and Pathogenesis

PPFE is fundamentally a fibrotic process involving the pleura and subpleural lung parenchyma with elastotic fibrosis, not a reactive process to cavitary disease 1. The condition can be:

• Idiopathic - occurring without identifiable cause 1
• Secondary - associated with specific conditions including:
  • Recurrent infections (approximately 50% of patients) 1
  • Drug exposures (daptomycin, dapsone) 2, 3
  • Post-hematopoietic stem cell transplantation/chemotherapy complications 4
  • Coexistent with other interstitial lung diseases (IPF, other IIPs) 5, 4
  • Rarely associated with connective tissue diseases 2

The Relationship Between PPFE and Lung Injury

The evidence suggests PPFE represents a pattern of chronic lung injury rather than a consequence of pre-existing structural abnormalities like cavitations 3. Key mechanistic insights include:

• PPFE may develop when repeated inflammatory alterations from pulmonary infections contribute to disease development/progression 2
• The disease is characterized by multilobar subpleural and/or centrilobular fibrous interstitial pneumonia with extensive (>80%) proliferation of elastic fibers 3
• This represents a primary fibroelastic proliferative process, not secondary scarring from cavitary disease 3

Clinical Features That Distinguish PPFE

PPFE has distinct characteristics that argue against it being secondary to cavitations 1, 5:

• Upper lobe predominance with dense subpleural consolidation, traction bronchiectasis, and architectural distortion 1, 5
• Pneumothorax is common (occurring in approximately 80-90% of cases in some series) 1, 6
• Recurrent infections occur in approximately half of patients, but these appear to be complications rather than causes 1
• Progressive disease occurs in 60% with 40% mortality from disease 1

Important Clinical Pitfall

The critical distinction is that cavitations do not cause PPFE; rather, PPFE creates conditions (pleural fibrosis, architectural distortion, recurrent pneumothorax) that may secondarily lead to infectious complications or air-filled spaces 1, 6. The severe mechanical restriction with high RV/TLC ratio and eventual hypercapnic respiratory failure are consequences of the primary fibroelastic process, not reactions to pre-existing cavitary disease 6.

Diagnostic Approach

When evaluating a patient with upper lobe abnormalities, consider 1, 5:

• Look for characteristic HRCT features: dense subpleural consolidation with traction bronchiectasis, pleural-based opacities, and upper lobe volume loss 1, 5
• Assess for pneumothorax history: highly suggestive of PPFE when present with upper lobe fibrosis 1, 5
• Evaluate temporal sequence: PPFE develops over months to years, not acutely following cavitary disease 1
• Consider alternative diagnoses: cavitary upper lobe disease suggests mycobacterial infection, fungal infection, or necrotizing processes—fundamentally different pathophysiology from PPFE 1