lung



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  • Normal

    • alveoli
    • interstitium
      • airways
      • vessels
    • developmental stages
      • embryonic: 3-7 weeks, tubules, pseudostratified lining
      • pseudoglandular: 7-16 weeks, denser tubules (early), simple cuboidal lining with subnuclear vacuoles (late)
      • canalicular: 2nd trimester, branched tubules, cuboidal lining
      • saccular: 3rd trimester, flat lining, losing interstitial mesenchyme
      • alveolar: mid 3rd trimester, back-to-back alveoli (loss of mesenchyme)
  • medical

  • neoplasm

  • Grading

    • Grade1: lepidic pattern or well differentiated
    • Grade2: acinar, papillary patterns, or moderately differentiated
    • Grade3: micropapillary, solid, mucinous, or poorly differentiated
    • Grade4: small cell carcinoma, large cell carcinoma, or undifferentiated
  • TNM (useful for grossing)

    • T1: <= 3cm or superficial spreading
    • T2
      • > 3cm
      • involves main bronchus, >= 2cm distal to carina
      • invades visceral pleura (disrupts elastic layer, do elastin stain)
      • partial atelectasis or obstructive pneumonitis
    • T3
      • involves...
        • chest wall
        • diaphragm
        • mediastinal pleura
        • parietal pericardium
        • main bronchus, < 2cm distal to carina
      • entire lung atelectasis or obstructive pneumonitis
    • T4
      • involves...
        • mediastinum
        • heart
        • great vessels
        • trachea
        • esophagus
        • vertebral body
        • carina
      • separate nodules in the same lobe
      • malignant pleural effusion
    • superficial spreading: invasion limited to bronchial wall
    • Regional nodes: intrathoracic, scalene, supraclavicular
    • N1: ipsilateral peribronchial, hilar, or intrapulmonary
    • N2: ipsilateral mediastinal or subcarinal
    • N3
      • contralateral mediastinal or hilar
      • scalene or supraclavicular
    • M1: distant metastasis, including separate nodule in different lobe
  • Staging

    • 0: Tis
    • IA: T1
    • IB: T2
    • IIA: T1N1
    • IIB: T2N1 or T3
    • IIIA: T3N1 or N2
    • IIIB: T4 or N3
    • IV: M1