Bronchioloalveolar Cell Carcinoma

Epidemiology

  • Bronchioloalveolar cell carcinoma accounts for 4-29% of non-small cell lung cancers
  • Females account for 50-70% of all cases
  • Less association with smoking, as compared to other lung cancer subtypes
  • Increasing incidence (from 9.3% before 1978 -> 20.3% in 1986-1989 period)

Risk Factors

  • Pulmonary fibrosis or scarring
  • Occupational lung disease
  • Previous Exogenous [[Lipoid Pneumonia]]

Pathology

  • Subtype of adenocarcinoma
  • Lepidic growth pattern without stromal, vascular, or pleural invasion
  • Histologic Subtypes
    • Non-mucinous (60-80% of cases): usually localized and has a lower frequency of bronchogenic spread
      • Proliferation of Clara cells or type II pneumocytes
    • Mucinous (20-40% of cases)
      • Proliferation of goblet cells or mucin-producing columnar cells
      • Mucous-filled alveoli -> appear radiographically as consolidation

Diagnosis

  • CXR/CT Patterns
    • Solitary Peripheral Pulmonary Nodule (43% of cases): usually slow-growing and localized
      • May present as focal ground-glass or ground-glass with consolidation on CT
      • This radiographic pattern has the best prognosis
    • Multiple Pulmonary Nodules (27% of cases):
      • May present with multiple bilateral nodules
      • Nodules may be well or poorly-defined
      • Nodules may cavitate
      • This radiographic pattern has the worst prognosis
    • Lobar Consolidation (30% of cases): reflects mucin production and tumor growth along alveolar walls
      • Due to copious mucin production, may present with bulging fissure sign (see [[CXR-Bulging-Sagging Fissure Sign]]):
      • This radiographic pattern has intermediate prognosis
    • Lymphangitic Pattern:
    • Pleural Effusion:
    • Atelectasis:
    • Pneumothorax: rarely seen
  • PET Scan
    • Low sensitivity (only positive in 60% of cases): due to slow growth and relatively maintained differentiation
    • Sensitivity is even lower (38% of cases) with solitary nodule pattern of presentation

Clinical

(most patients are symptomatic at the time of diagnosis)

  • Cough
  • Sputum production
  • Hemoptysis
  • Weight loss
  • Fever
  • Bronchorrhea: uncommon and usually occurs late in the course (and with diffuse disease)

Treatment

  • Localized disease: lobar resection and ipsilateral mediastinal lymph node resection
  • Advanced disease: chemotherapy and biologic agents, specifically epidermal growth factor receptor-tyrosine kinase (EGFR-TK) inhibitors, have been used
    • Emerging evidence shows that female sex, nonsmoking status, Asian ethnicity, and the presence of EGFR-TK mutations predict responsiveness to these agents

Prognosis

  • Peripheral adenocarcinoma with a pure bronchioloalveolar cell carcinoma pattern has 100% 5-year survival in contrast to adenocarcinoma with invasive growth pattern that has a survival rate of 52% in 5 years
  • Mixed adenocarcinoma with bronchioloalveolar cell carcinoma features has a survival rate of 75%
  • Studies have shown that increasing proportions of bronchioloalveolar cell carcinoma features on histology also correlates with better outcomes

References

  • A 42-Year-Old Woman With Diffuse Pulmonary Infiltrates and Bilateral Pneumothoraces. Chest 2011; 140(2):550–553
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