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Incidental Pulmonary Nodule (Fleischner 2017)

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Fleischner Society 2017·reviewed 2026-07-01
  • Applies to incidentally detected nodules in patients ≥35 years. Do NOT apply to lung-cancer screening (use Lung-RADS), patients <35 years, known primary malignancy, or immunosuppressed patients.
  • Size = mean of long- and short-axis diameters on the same section, rounded to the nearest mm; thresholds are read as nodule volume equivalents (<6 mm ≈ <100 mm³; 6–8 mm ≈ 100–250 mm³; >8 mm ≈ >250 mm³).
  • Low vs high risk reflects clinical probability of malignancy: high risk = older age, heavy smoking, upper-lobe location, spiculated margin, emphysema/fibrosis, or family history. Low risk applies to minimal or absent risk factors.
  • For subsolid nodules the relevant sub-measurement is the SOLID component: a solid component ≥6 mm markedly raises concern and generally warrants closer follow-up or intervention.
  • For multiple nodules, base management on the most suspicious nodule; scattered tiny nodules are often infectious/benign.
  • These are minimum follow-up recommendations; morphologically suspicious nodules (spiculation, upper-lobe) may be managed more aggressively at the reader's discretion.

Does the patient qualify for Fleischner criteria?

Patient ≥35 years, no known primary cancer, not immunosuppressed, and this is not a lung-cancer screening exam.

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Sources

  • MacMahon H, et al. Guidelines for Management of Incidental Pulmonary Nodules Detected on CT Images: From the Fleischner Society 2017. Radiology. 2017;284(1):228-243.source
  • Bankier AA, et al. Fleischner Society: Glossary of Terms for Thoracic Imaging. Radiology. 2024;310(2):e232558.source

Educational reference for clinicians — not medical advice. Verify against the primary source before acting on it; guidelines change. Final decisions rest with the interpreting physician and your institution's protocols.