Etymology
- Derived from the Greek words bronchos, meaning “windpipe,” and kele, meaning “swelling.” The term refers to a pathological dilatation of a bronchus filled with mucus.
AKA
- Mucoid impaction
- Bronchial mucocele
What is it?
- A bronchocele is a dilated bronchus filled with mucus, typically resulting from obstruction of the bronchial lumen by intrinsic or extrinsic factors. It appears as a branching tubular or cystic opacity on imaging.
Caused by:
- Most common causes:
- Obstruction due to bronchial atresia
- Allergic bronchopulmonary aspergillosis (ABPA)
- Less common causes:
- Infection:
- Tuberculosis
- Fungal infections
- Neoplasm:
- Endobronchial tumors (e.g., carcinoid tumors, adenoma)
- Mechanical:
- Extrinsic compression by lymphadenopathy or masses
- Congenital:
- Bronchial atresia
- Other:
- Post-obstructive mucoid impaction
- Infection:
Resulting in:
- Mucus retention and airway dilation
- Localized or diffuse airflow obstruction
- Recurrent infections
Structural Changes:
- Bronchial dilation distal to obstruction
- Mucus plugging within the lumen
- Secondary inflammation or infection in surrounding lung tissue
Pathophysiology:
- Obstruction of a bronchus leads to mucus accumulation and stasis, causing dilatation of the affected airway. Chronic obstruction may result in secondary infection or inflammation, further compromising pulmonary function.
Pathology:
- Mucus-filled bronchial lumen
- Thickened bronchial walls
- Inflammatory infiltrates in cases of secondary infection
Diagnosis
Clinical:
- Symptoms include:
- Chronic cough
- Hemoptysis in some cases
- Recurrent pulmonary infections
- Asymptomatic in some cases (incidental finding on imaging)
Radiology:
- CXR:
- Tubular or branching opacity, often described as a “finger-in-glove” appearance
- Localized hyperinflation if associated with obstruction
- CT of the Chest:
- Tubular or cystic branching opacities
- Central low attenuation (mucus-filled lumen)
- Associated findings such as bronchial wall thickening, consolidation, or air trapping
Labs:
- Sputum culture to identify infectious organisms
- Fungal serologies or IgE levels in cases of ABPA
Management:
- Targeted treatment:
- Antibiotics for secondary infections
- Antifungal therapy in ABPA
- Surgical resection in cases of localized obstruction (e.g., bronchial atresia or tumors)
- Supportive care:
- Airway clearance techniques
- Bronchodilators in cases of associated airway obstruction
Radiology Detail
CXR
Findings:
- Finger-in-glove tubular opacities
- Localized hyperinflation or consolidation
Associated Findings:
- Atelectasis or collapse distal to obstruction
CT of the Chest
Parts:
- Segmental and subsegmental bronchi
Size:
- Dilated airways with mucus-filled lumens
Shape:
- Tubular or branching morphology
Position:
- Often located in the upper lobes (e.g., bronchial atresia)
Character:
- Low attenuation within dilated bronchi
- Bronchial wall thickening in chronic cases
Time:
- Chronic, with potential acute exacerbations due to superimposed infection
Associated Findings:
- Secondary infection, consolidation, or air trapping
Other relevant Imaging Modalities
MRI/PET CT/NM/US/Angio:
- MRI: Rarely used but may provide soft tissue characterization
- PET-CT: Useful for assessing endobronchial neoplasms
Pulmonary Function Tests (PFTs):
- Obstructive or mixed patterns depending on the extent of involvement
Recommendations:
- CT of the Chest for detailed evaluation of bronchocele and associated abnormalities
- Treat underlying causes to prevent progression or complications
- Consider surgical evaluation for persistent or recurrent cases
Key Points and Pearls:
- A bronchocele represents a mucus-filled, dilated bronchus often seen in conditions like bronchial atresia or ABPA.
- The “finger-in-glove” appearance on imaging is a hallmark feature.
- CT of the Chest is essential for detailed assessment and identification of underlying causes.
- Management focuses on treating the cause, addressing infections, and supporting airway clearance.
Differences Between a
Bronchocele and Bronchiectasis
Feature | Bronchocele | Bronchiectasis |
---|---|---|
Definition | Mucus-filled, dilated bronchus | Permanently dilated bronchus |
Cause | Airway obstruction | Chronic inflammation and infection |
Pathophysiology | Obstruction leads to mucus stasis | Wall destruction leads to dilation |
Radiology | Tubular “finger-in-glove” opacity | Signet ring sign; lack of tapering |
Reversibility | Potentially reversible | Irreversible |