Part 1 · Miscellaneous Lung Diseases

Interstitial Lung Disease

When medical diagnosis is insufficient — surgical biopsy indications, approach, and site selection in ILD.

Surgical relevance

Overview — the surgeon's role

Interstitial lung disease (ILD) encompasses a heterogeneous group of diffuse parenchymal lung disorders characterised by inflammation and fibrosis of the lung interstitium. The thoracic surgeon's role in ILD is primarily diagnostic — surgical lung biopsy when less invasive methods are insufficient for a definitive histopathological diagnosis. Surgical intervention for complications (pneumothorax, lung cancer in ILD) is a secondary role.

Classification

ILDs are classified as: idiopathic interstitial pneumonias (IIP — including IPF, NSIP, COP, DIP, LIP, AIP); ILD secondary to systemic disease (CTDs — RA, SLE, systemic sclerosis, polymyositis); granulomatous ILD (sarcoidosis, HP); and rare ILDs (LAM, eosinophilic pneumonia). The specific histopathological pattern — UIP, NSIP, OP, DIP — guides prognosis and treatment.

Surgical lung biopsy

When non-invasive investigation (HRCT, BAL, serological testing) does not yield a confident diagnosis, and where the histopathological pattern will meaningfully alter management, surgical lung biopsy should be offered.

Indications for surgical biopsy

  • Atypical HRCT pattern or clinical features inconsistent with IPF/UIP
  • Discordant clinical, radiological, and BAL findings
  • Suspected alternative diagnosis (malignancy, COP, DIP) that would change treatment
  • Baseline histology required for clinical trial eligibility

Contraindications

  • Definite UIP pattern on HRCT with typical clinical context — multidisciplinary diagnosis of IPF does not require histology
  • Severe functional impairment — predicted post-operative mortality exceeds the diagnostic benefit
  • Acute exacerbation of ILD — surgical biopsy in this context carries >30% mortality

VATS vs. open biopsy

Surgical approach — comparison
VATS (preferred)Lower morbidity · shorter LOS · equivalent diagnostic yield · better tolerated in borderline lung function
Open (mini-thoracotomy)When VATS not feasible · severe pleural adhesions · haemodynamic instability · better access for extensive sampling

Site selection for biopsy

Critical principle — site selection

Always biopsy the transition zone between normal and diseased lung — not end-stage fibrotic lung and not grossly normal lung. End-stage fibrotic lung (honeycomb pattern) yields only architectural distortion with no diagnostic pattern. The middle lobe and lingula should be avoided — these show non-specific changes in the majority of ILDs regardless of underlying diagnosis. Always obtain multiple biopsies from different lobes.

Post-biopsy complications

Common Prolonged air leak Atelectasis
Serious Acute exacerbation of ILD Respiratory failure Death (1–3% in IPF)

Acute post-operative exacerbation of ILD is the most feared complication — presenting within days of surgery with acute respiratory worsening, new bilateral ground-glass changes, and requirement for ICU-level care. Mortality is high. Risk is highest in severe IPF with FVC <60% predicted.

Current ILD treatment guidelines

Antifibrotic therapy (nintedanib, pirfenidone for IPF), immunosuppression for CTD-ILD, and management of ILD complications are managed by respiratory physicians. Refer to ERS/ATS ILD guidelines for current treatment protocols.

Further reading

All clinical content should be verified against current guidelines before clinical application. This resource is intended for revision and educational purposes only.

Standard textbooks

  • Shields TW, LoCicero J, Reed CE, Feins RH. General Thoracic Surgery. 7th ed. Lippincott Williams & Wilkins.
  • Sellke FW, del Nido PJ, Swanson SJ. Sabiston & Spencer Surgery of the Chest. 9th ed. Elsevier.
  • Pearson FG, et al. Thoracic Surgery. 3rd ed. Churchill Livingstone.

Current guidelines & resources