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Lung Masses

Sybil Watkins, Chandler Montgomery

Background

  • Definitions: lesion < 3 cm = pulmonary nodule. Lesion > 3 cm = lung mass

    • Pulmonary nodules are common and often benign, but presence of lung mass (>3cm) should prompt workup as chance of malignancy is high (>50%)
    • Refer to “Pulmonary Nodule” chapter

  • Differential diagnosis:

    • Malignant
      • Primary non-small cell lung cancer (NCSLC): adenocarcinoma (~40%), squamous cell (SCC, ~20%), large cell carcinoma (~5%)
      • Metastatic: commonly melanoma, sarcoma, colon, breast, renal, testicular
      • Often multiple nodules/masses (e.g. cannonball)
      • Neuroendocrine: small cell lung cancer (SCLC, ~15%), carcinoid, large cell neuroendocrine
    • Infectious
      • Granulomatous: TB, non-TB mycobacterium, endemic fungal (histo, blasto, coccidio)
      • May have component of calcification
      • Abscess: Staph aureus, Klebsiella, anaerobes, polymicrobial (aspiration)
      • Septic emboli, hydatid cyst, aspergilloma
    • Other: hamartoma, AVM, pulmonary infarct, inflammatory nodule (GPA, RA), sarcoidosis

Evaluation

  • History: smoking, cough, hemoptysis, dyspnea, chest pain, weight loss, fevers, night sweats,hoarseness (recurrent laryngeal nerve involvement), bone pain, FND, Horner’s syndrome

    • Lung cancer should always be considered in a pt with recurrent pneumonia (post-obstructive) or smoking history with new cough or hemoptysis

  • Exam: cachexia, LAD, bone pain, hepatomegaly, FND, SVC syndrome, digital clubbing

  • Imaging

    • CXR has poor sensitivity for lung nodules, may show large mass or malignant effusion
    • CT chest (with contrast if possible—better evaluation of mediastinum/LNs)
      • Review prior chest imaging to assess age and growth pattern of lesion(s)
      • Benign features: small (sub-centimeter), calcified, fat attenuation, stable over 2 years, multiple nodules
      • Concerning features: large, growth, spiculation, upper lobe location, thick-walled cavitation, mediastinal invasion
      • Location: adenocarcinoma often more peripheral, SCC often more central, SCLC associated with massive LAD, mediastinal invasion, and large hilar masses

  • Look for paraneoplastic syndromes

    • SCLC: SIADH, Lambert-Eaton, Cushing’s syndrome
    • SCC: hypercalcemia (PTHrP)
    • Dermatomyositis, polymyositis, hypertrophic pulmonary osteoarthropathy (periostitis of long bones)
    • Maranticendocarditis
    • Hypercoagulabilityleadingtovenousthromboembolism

Staging/Diagnosis

  • Imaging: CT chest (with contrast if possible) and CTAP w/contrast vs. PET/CT to assess for metastasis. Consider MRI brain if clinical stage III or IV disease
  • Biopsy: careful planning is key
    • For metastatic disease, obtain tissue from least invasive site
      • FNA or excision of palpable lymph node (cytology dept, US-guided procedure, EGS)
      • Pleural effusion: thoracentesis w/ cytology might provide initial info (sensitivity ~60%)
    • If uncertain how to best obtain tissue, consult IR, interventional pulm, and/or oncology to discuss approach
      • Surgical Bx: Wedge resection/lobectomy often preferred if solitary nodule amenable to both diagnostic and therapeutic resection in good surgical candidate
      • Bronchoscopy with EBUS (endobronchial US) often used to obtain biopsy of mediastinal tissue or central/peri-bronchial lesion
      • Navigational bronchoscopy: allows for more precise maneuvering of scope/instrument into the periphery of the lungs under direct visualization while ensuring stability during sampling of target lesions; increased diagnostic yield
      • Trans-thoracic needle aspiration (TTNA): peripheral lesions not amenable to bronchoscopy

Management

  • NSCLC: Planning is complex, usually discussed at multidisciplinary tumor board

    • Stage I/II: surgical resection ± adjuvant chemotherapy
    • Stage III: more complex requiring multidisciplinary approach, typically combined chemoradiotherapy specifically with immunotherapy agents
    • Stage IV: chemo ± targeted therapy depending on PD-L1 expression, presence of driver mutations for EGFR, ALK, ROS-1, BRAF, MET, RET, others

  • SCLC: usually widely metastatic at time of diagnosis (~70%), treated with systemic chemo/radiation specifically with immunotherapy agents