Lung Nodule

David Krasinski

Background 

  • Definition: focal, distinct radiographic density completely surrounded by lung tissue <3cm (mass >3cm – see “Lung Mass” chapter)
  • Prevalence: 30% of all chest CTs. Most commonly are incidentalomas. >95% are benign. Larger and irregularly shaped nodules are more likely to be malignant.

Etiologies

CT Pattern

Pathology

Etiologies
Random: hematogenous spread. Infections Miliary TB, septic emboli
Malignancy Sarcomas, carcinomas
Other Langerhans cell histiocytosis
Centrilobular: most diseases that track airways Infectious Granulomas from fungi, mycobacteria, prior bacterial infx (nocardia/S. aureus).
Inflammatory Aspiration, hypersensitivity pneumonitis, bronchogenic cyst.
Malignancy Bronchogenic carcinomas (central: SCC, small-cell), peripheral (adenoCa, large cell)
Peri lymphatic: lymph system spreadgret Inflammatory Sarcoidosis, pneumoconiosis
Malignant Lymphangitic carcinomatosis, lymphoma, metastatic sarcomas/carcinomas
Benign Hamartomas, fibromas, hemangiomas, leiomyomas, amyloidoma.

Management of solitary lung nodule 

  • History: hx of exposures (tobacco, asbestos, mining, biomass fuel), geographical epidemiology (histo/coccidio/TB), B-symptoms, personal and FxHx of malignancy
  • Assess pt risk for malignancy
    • High risk: >60yo, current smoker or heavy smoking history, history of cancer, FxHx lung cancer, irregular or spiculated, upper lobe, ≥2.3cm, double diameter or volume in past year
    • There are online risk calculators (Brock, Mayo, Herder) helpful for providers who are not experts in lung nodule risk stratification
  • Benign imaging features: central calcification, popcorn-like (hamartomas), laminated, stippled
  • Consider Pulmonary referral if high risk features, known malignancy or recent history of malignancy, organ transplant or other immunocompromising condition, age <35yo

Fleischner guidelines for nodules <8mm

Risk for Malignancy

Solid <6mm

Solid 6-8mm

Solid ≥8mm

Subsolid (GGO ± solid component)
Low No follow-up CT at 6-12mo and consider at 18-24mo Refer to Pulm. CT in 3mo. Consider PET + tissue sampling* If >6mm, refer to Pulm. If malignant, may be slow growing. Requires follow up to 5 years. Initially every 6mo
High Optional CT in 12mo CT at 6-12mo and at 18- 24mo

*Tissue sampling usually occurs via transthoracic needle biopsy (via IR), VATS (via thoracic surgery), or transbronchial biopsy (via interventional pulm).

ACCP 2013 Chest Guidelines for workup of nodules 8-30mm

Low to Moderate Risk Surical Risk 

  • Assess clinical probablility of cancer
    • Very low (< 5%)
      • CT surveillance
    • Low/mod (5-65%)
      • PET to assess nodule
      • à Negative or mild uptate: CT surveillance OR nonsurgical biopsy
      • àMod or intense uptake: nonsurgical biopsy or surgical resection
    • High (> 65%)
      • Standard stage eval (±PET)
      • à No met: Surgical resection or SBRT or RFA
      • à + Met (N2, 3): chemotherapy or chemoradiation (after biopsy) 

High Surgical Risk 

  • Nonsurgial biopsy OR
    • Malignant
      • Standard stage eval (±PET)
      • à No met: Surgical resection or SBRT or RFA
      • à + Met (N2, 3): chemother apy or chemoradi ation (after biopsy)
    • Nondiagnostic
      • CT surveillance
    • Specific Benign
      • Specific treatment
  • CT surveillance
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