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
- Non-mucinous (60-80% of cases): usually localized and has a lower frequency of bronchogenic spread
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
- Solitary Peripheral Pulmonary Nodule (43% of cases): usually slow-growing and localized
- 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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