Lung nodule and lung mass

From greek.doctor
  • Lung anatomy
    • Primary lung lobule
      • Not so important in radiology
    • Secondary lung lobule
      • Represent a cluster of up to 30 acini supplied by a common distal pulmonary artery and bronchiole
      • Have polyhedral shape
      • Bounded by intralobular septa
        • Are visible as Kerley B lines in pulmonary oedema
  • Lung mass < 3 cm = nodule
  • Lung mass > 3 cm = mass
  • Modalities
    • X-ray
    • CT
    • PET
  • Benign vs malignant
    • Characteristics of benign masses
      • Age < 40
      • Small (< 3 cm)
      • Round
      • Well-defined edges
      • Slow growth over time (years)
        • Comparison with older images is important!
      • Solid
      • Central, laminar or diffuse calcification
    • Characteristics of malignant masses
      • Age > 40
      • Large (> 3 cm)
      • Irregular shape
      • Poorly defined edges
      • Obvious growth over time
      • Cavitated
      • Active accumulation of FDG on PET scan
  • Indirect signs of lung mass
    • Atelectasis
    • Postobstructive pneumonia
    • Pleural effusion
    • Hilar adenopathy
  • High risk
    • Smoker
    • > 40 years
    • Clinical symptoms suspicious of cancer
      • Haemoptysis
      • Weight loss
      • Hoarseness
    • Mass has malignant characteristics on imaging
  • If mass and/or patient is high risk -> investigation
    • CT
      • Also for small peripheral lung masses
    • PET
    • Biopsy
  • Differential diagnosis
    • Granuloma
      • TB
      • Histoplasmosis
    • Hamartoma
    • Primary lung cancer
      • Usually solitary nodule
      • Adenocarcinoma
        • Peripheral mass
      • Squamous cell carcinoma
        • Central mass
      • Small cell carcinoma
        • Hilar mass
    • Metastases
      • Usually multiple nodules
    • Round pneumonia
  • If tumor in apex of lung = Pancoast tumor
  • Multiple lung nodules must always be examined with CT

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