• Multiple intrabronchial nodules

What is it?
Endobronchial nodules refer to multiple nodules located within the bronchial tree, often resulting from infectious, inflammatory, or metastatic processes. These are distinct from solitary endobronchial neoplasms.

Caused by:

• Infection:
  • Endobronchial spread of tuberculosis
  • Fungal infections (e.g., aspergillosis, cryptococcosis)
  • Viral or bacterial infections with debris or granulomas
• Inflammation:
  • Allergic bronchopulmonary aspergillosis (ABPA) with mucus and nodular inflammation
  • Bronchocentric granulomatosis
• Neoplasm (secondary):
  • Endobronchial metastases from extrapulmonary malignancies (e.g., renal cell carcinoma, melanoma)
• Immune-related:
  • Sarcoidosis with endobronchial granulomas
  • Granulomatosis with polyangiitis (GPA)
• Iatrogenic:
  • Retained surgical materials causing inflammatory nodules
• Congenital or Inherited:
  • Bronchial atresia with nodular mucus impaction
• Trauma:
  • Granulation tissue secondary to airway injury or instrumentation

Resulting in:

• Airway narrowing or obstruction
• Post-obstructive pneumonia or atelectasis
• Bronchial thickening

Structural Changes:

• Multiple nodules confined within the bronchial lumen
• Bronchial wall thickening
• Mucus plugging with secondary infection

Pathophysiology:

• Infections causing endobronchial seeding
• Inflammatory processes leading to airway wall thickening and nodule formation
• Neoplastic spread through hematogenous or direct extension

Pathology:

• Infectious: Granulomatous inflammation with caseation (e.g., tuberculosis)
• Neoplastic: Tumor cell clusters within the bronchial lumen
• Inflammatory: Granulomas with eosinophilic material (e.g., ABPA)

Diagnosis:

• Clinical history with risk factors (e.g., immunocompromised state, history of malignancy)
• Imaging and bronchoscopy findings

Clinical:

• Cough, hemoptysis, and post-obstructive pneumonia
• Wheezing or dyspnea from airway narrowing

Radiology:

CXR:

• Findings: Indirect signs like airway obstruction with atelectasis or post-obstructive consolidation
• Associated Findings: May show branching opacities if nodules are associated with mucus plugging

CT:

• Parts: Multiple nodules within the bronchial lumen with airway thickening
• Size: Nodules range from 1–10 mm
• Shape: Round, oval, or irregular
• Position: Segmental or lobar distribution
• Character: Soft tissue density nodules, sometimes cavitating
• Time: Nodules may resolve (e.g., infections) or progress (e.g., metastases)

Bronchoscopy:

• Visualizes multiple intrabronchial nodules, often as polypoid lesions
• Allows for sampling to determine etiology

PET-CT:

• Useful for assessing metabolic activity in suspected malignancies

Other Imaging Modalities:

• MRI: Rarely used for intrabronchial nodules

Pulmonary Function Tests (PFTs):

• May show obstruction in cases of significant airway involvement

Management:

• Imaging:
  • High-resolution CT for detailed nodule evaluation
• Bronchoscopy:
  • Essential for sampling nodules
• Microbiological Workup:
  • Sputum and bronchial lavage cultures
• Histopathological Analysis:
  • Biopsy if malignancy or granulomatous disease suspected

Recommendations:

• High-resolution CT for number, size, and distribution of nodules
• Bronchoscopy for direct visualization and sampling
• Microbiological and cytological analysis for suspected infections and malignancy

Key Points and Pearls:

• Multiple endobronchial nodules are often due to infectious or metastatic processes rather than primary airway neoplasms.
  

  “Multiple endobronchial nodules commonly arise from infections, such as tuberculosis or metastatic disease.” Radiopaedia

• Secondary endobronchial involvement from metastases or granulomatous diseases should be carefully considered.
  

  “Endobronchial metastases often originate from renal cell carcinoma, breast cancer, and melanoma, necessitating further workup.” Radiopaedia

• Post-obstructive changes such as atelectasis or pneumonia may offer diagnostic clues.
  

  “Post-obstructive consolidation and atelectasis often occur secondary to bronchial obstruction from nodular lesions.” Radiographics

• Resolution of nodules over time suggests a benign or infectious cause, while progression may indicate metastatic disease.
  

  “Nodules that resolve over time are frequently related to transient infections, whereas progressive nodularity may suggest neoplasia.” RadiologyKey