Uncategorized

• What is it:
  • A lung mass is a localized area of abnormal tissue growth.
  • It is found within the lung parenchyma,
  • A mass is defined as
    • measuring greater than 3 cm in diameter.
  • It can be benign or malignant and
  • often requires further investigation.
• Etymology:
  • The term “mass” derives from the Latin word massa.
  • Massa means “lump” or “bulk.”
• AKA:
  • Pulmonary mass.
  • Intrapulmonary lesion (non-specific).
• How does it appear on each relevant imaging modality:
  • Chest CT (preferred):
    • Shows solid, mixed, or cystic components.
    • Larger size (>3 cm) correlates with a higher likelihood of malignancy.
    • Shape may be round, oval, or lobulated.
    • Spiculated or irregular margins may suggest malignancy.
    • Calcifications can appear a
      • central,
      • popcorn-like (hamartoma), or
      • eccentric patterns.
    • Post-contrast enhancement may be
      • uniform (benign) or
      • heterogeneous (malignant).
    • May be
      • bronchocentric or have
      • air bronchograms
  • Chest X-ray:
    • Appears as a
      • solitary or
      • multiple rounded opacity.
    • Spiculated margins
      • raise suspicion of malignancy.
    • Limited in assessing internal characteristics compared to CT.
  • MRI:
    • Rarely used but helpful for soft tissue characterization.
    • Useful for assessing vascular invasion.
    • Malignant lesions are typically
      • T1 hypointense and
      • T2 hyperintense.
  • • High metabolic activity
      • (high SUV uptake)
        • >2.5 significant and suspicious
        • >3-4 highly concerning very suspicious
      • strongly suggests malignancy.
    • Benign lesions
      • like hamartomas generally have
      • low SUV uptake. (<2.5)PET-CT:
  • Ultrasound:
    • Rarely used for lung masses.
    • Useful for pleural-based lesions or guiding biopsies.
• Differential diagnosis:
  • Infectious: Tuberculoma, fungal mass (e.g., aspergilloma), abscess.
  • Inflammatory: Rheumatoid nodule, granuloma (e.g., sarcoidosis).
  • Neoplastic:
    • Benign: Pulmonary hamartoma, leiomyoma.
    • Malignant:
      • Primary: Non-small cell lung cancer (adenocarcinoma, squamous cell carcinoma, large cell carcinoma) or small cell carcinoma.
      • Secondary: Metastases (e.g., from breast, colon, kidney).
  • Mechanical: Pseudomass due to rounded atelectasis.
  • Trauma: Hematoma.
  • Circulatory: Pulmonary artery aneurysm or arteriovenous malformation.
  • Congenital: Bronchogenic cyst or pulmonary sequestration.
• Recommendations:
  • Further imaging:
    • PET-CT for metabolic characterization and staging if malignancy is suspected.
    • Contrast-enhanced CT to evaluate vascularity and internal characteristics.
  • Tissue diagnosis:
    • Biopsy (CT- or ultrasound-guided) or bronchoscopy for histopathological analysis.
  • Follow-up imaging:
    • Short-term interval CT for indeterminate lesions.
  • Additional work-up:
    • Tumor markers or microbiological studies (if infection is suspected).
• Key considerations and pearls:
  • Spiculated margins, larger size, and metabolic activity on PET-CT are key indicators of malignancy.
  • Central masses often correlate with primary lung cancer.
  • Peripheral masses may suggest metastases or infections.
  • Assess for associated findings such as mediastinal lymphadenopathy, pleural effusion, or chest wall invasion.
  • Correlate imaging findings with clinical history, such as smoking, systemic symptoms, or prior malignancy.