Solitary Pulmonary Nodule

Gerald W. Staton, Jr., M.D., F.A.C.P. Emory University School of Medicine

Definition/Key Clinical Features
Differential Diagnosis
Best Tests
Best Therapy
Best References


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Definition/Key Clinical Features

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Differential Diagnosis

Infectious Diseases



Neoplastic Diseases

Noninfectious, Nonneoplastic Disorders

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Best Tests

Aids in Diagnosis of Malignancy


  • Patient age
    • < 45 yr: low risk
    • > 60 yr: high risk
    • Cigarette smoking
      • Never smoked: low risk
      • Current smoker: high risk
Lesion Size

  • < 1.5 cm: low risk
  • ≥ 2.3 cm: high risk

Pattern of Lesion Margin

  • Corona radiata (fine strands extending from lesion): high risk
  • Scalloped margins: intermediate risk
  • Smooth border: low risk
Calcification of Lesion

  • Stippled or eccentric calcification: high risk
  • Laminated or central calcification: granuloma
  • “Popcorn” calcification: hamartoma
Growth of Lesion

  • Old chest radiographs, CT scans reveal stability or growth
  • 30% increase in diameter = doubling of volume
  • Doubling in volume over > 1 mo and < 1 yr indicates malignancy
  • Stability for 2 years = benign in 65%
  • Follow-up imaging every 3 mo for 1 yr, then every 6 mo
    • CT can detect changes in size within 30 days

Noninvasive Diagnostic Methods

CT Densitometry

  • Lesions with greater density more likely benign
  • Lesion must be compared with a “phantom” for density calibration
  • Cutoff points: 185–264 Hounsfield units
Contrast-Enhanced CT

  • Enhancement of lesion of > 20 Hounsfield units
  • Sensitivity, 95%–100%; specificity, 70%–93%
Positron Emission Tomography

  • Differentiates benign from malignant nodules
  • Sensitivity, 97%; specificity, 78%
  • False positives: infectious, inflammatory lesions
  • False negatives: bronchoalveolar carcinoma, carcinoids, nodules < 1 cm
  • Can provide information for staging

Invasive Diagnostic Methods


  • Very poor yield with lesions < 1.5 cm
  • 40%–60% yield with lesions 2.5–3 cm
  • Enhanced yield with lesions close to bronchus
Transthoracic Fine-Needle Aspiration Biopsy

  • > 90% sensitivity for malignant lesions > 2 cm
  • Significant false negative rate with smaller, centrally located lesions

  • Video-assisted thoracic surgery for established or suspected malignancy in patients at low surgical risk

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Best Therapy

  • Most benign lesions require no therapy
  • Malignant lesions treated on basis of diagnosis
  • Primary lung cancer in good surgical candidates treated with lobectomy

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Best References

Detterbeck FC, et al: Chest 125:2294, 2004

Libby DM, et al: Chest 125:1522, 2004

Ost D, et al: N Engl J Med 348:2535, 2003

Ost D, Fein A: Curr Opin Pulm Med 10:272, 2004

Gerald W. Staton, Jr., M.D., F.A.C.P., has received grants for educational activities from GlaxoSmithKline and Boehringer Ingelheim GmbH and serves as an advisor to GlaxoSmithKline

January 2006