Infiltration Around and in Bronchioles

Infiltration of Lymphocytes Plasma Cells and Histiocytes into the walls of the Bronchioles and Small Airways
Artistic rendering shows a normal bronchiole (a) with early infiltration into the wall of the airway, (b) with progressive infiltration with luminal compromise (c) evolving into obliteration (d). This would result in centrilobular nodules radiologically. Subsequently there is necrosis and a thin walled cyst remains
Ashley Davidoff MD TheCommonVein.net  139264.lungs
Image a shows a normal bronchiole.  Smoking excites the Langerhans cell which in turn  induces attracts  early cellular interstitial infiltrates of surrounding the bronchiole (b) including  lymphocytes, macrophages, eosinophils, plasma cells, and fibroblasts.  The cellular infiltrate progresses in a peribronchial pattern with mass effect on the bronchiole which becomes narrowed (c) and eventually disappears, a nodules of varying size manifest in the bronchiole pathway, sometimes round but often spiculated as the inflammatory reaction extends into the interstitium  (d) The wall of the bronchiole breaks down and the cellular infiltrate may undergo necrosis resulting in thick walled cavities, sometimes round in shape (e)  and sometimes with bizarre shapes (f) Eventually the inflammation recedes and a thin walled cyst remains (g ,h) 
Ashley Davidoff MD TheCommonVein.net

Bronchocentric Disease

Category Details
What is it? A disease process affecting the bronchi, characterized by inflammation, necrosis, and fibrosis of the bronchial walls and surrounding structures.
Etymology Derived from “broncho-” (relating to the bronchi) and “centric” (centered around), indicating a disease process centered around the bronchi.
AKA Bronchocentric granulomatosis, Bronchocentric inflammation, Peribronchial disease
Characterized by
Bronchial wall thickening, luminal narrowing or obstruction, peribronchial fibrosis, cavitation, and inflammatory changes. resultant abnormal airflow patterns to affected regions
Anatomically affecting Primarily affects the bronchi and bronchioles, with potential extension to lung parenchyma and peribronchial structures.
Pathophysiology
Inflammatory, infectious, neoplastic, or immune-mediated processes lead to bronchial wall thickening, fibrosis, and luminal narrowing. These changes cause airflow obstruction, air trapping, and ventilation-perfusion (V/Q) mismatch. Chronic obstruction may result in hyperinflation, atelectasis, and impaired gas exchange, contributing to respiratory compromise..

Causes Include:

  • Most Common Causes:
    • Sarcoidosis
    • Tuberculosis
      • Other Infectious causes (fungal, mycobacterial)
    • Bronchogenic carcinoma
    • Hypersensitivity pneumonitis
    • Granulomatosis with polyangiitis (Wegener’s)

Other Causes Include:

Category Causes
Inflammation and Immune Disorders Eosinophilic pneumonia
Neoplasm (Malignant and Benign) Carcinoid tumor
Mechanical Trauma Foreign body aspiration
Metabolic Amyloidosis
Circulatory Pulmonary infarction
Immune IgG4-related disease
Infiltrative Langerhans cell histiocytosis (LCH)
Inherited and Congenital Cystic fibrosis
Iatrogenic Radiation-induced lung injury
Idiopathic Idiopathic nodular bronchiolitis
Functional No known direct functional disorders
Psychiatric and Psychological Factitious disorder (self-induced inhalation of irritants)

Histopathology

Feature Description
Bronchocentric granulomas Inflammatory nodules centered around bronchi
Eosinophilic and lymphocytic infiltration Presence of immune cells causing inflammation
Necrotizing granulomas Seen in infectious or immune-mediated cases
Fibrosis and airway obliteration Occurs in chronic disease progression

Imaging Radiology

Modality Findings
  • CT (Applied Anatomy)
  • Parts: Bronchi, peribronchial regions, lung parenchyma;
  • Size: Variable depending on inflammation or fibrosis;
  • Shape: Nodular, branching, or consolidative patterns;
  • Position: Peribronchial, often upper lobe involvement;
  • Character: Ground-glass opacities, bronchial wall thickening, cavitation;
  • Time: Acute vs. chronic presentation
CXR Hilar and peribronchial opacities, reticulonodular infiltrates, hyperinflation or volume loss
MRI Rarely used, but may show soft tissue involvement and vascular invasion
PET-CT Increased FDG uptake in inflammatory and neoplastic conditions; Differentiates benign vs. malignant processes
Other Investigations Labs: Elevated inflammatory markers (CRP, ESR), serum ACE (sarcoidosis), IgE (ABPA); PFTs: Obstructive or restrictive patterns depending on disease progression

Differential Diagnosis

Disease Differentiating Features
Sarcoidosis Bilateral hilar lymphadenopathy, upper lobe fibrosis
Hypersensitivity pneumonitis Centrilobular nodules, mosaic attenuation
Tuberculosis Upper lobe cavitary lesions, tree-in-bud nodules
Granulomatosis with polyangiitis (Wegener’s) Necrotizing granulomas, renal involvement
Bronchogenic carcinoma Spiculated lung mass, mediastinal lymphadenopathy
Eosinophilic pneumonia Peripheral ground-glass opacities, eosinophilia
IgG4-related disease Peribronchovascular thickening, systemic organ involvement

Recommendations

Action Purpose
Perform high-resolution CT Better characterization of nodular and inflammatory changes
Consider bronchoscopy with biopsy Histopathological confirmation
Treat underlying causes Corticosteroids for immune-mediated disease, antibiotics for infections, chemotherapy for neoplasms
Monitor disease progression Serial imaging and pulmonary function tests

Key Points and Pearls

Key Point Clinical Significance
Bronchocentric nodules Suggest granulomatous and inflammatory diseases
Upper lobe predominance Common in sarcoidosis, TB, and Langerhans cell histiocytosis
Tree-in-bud nodules Suggest infectious or aspiration-related pathology
Cavitary nodules Consider vasculitis, infection, or malignancy
Early diagnosis Prevents irreversible airway damage in immune-mediated and infectious conditions

 

Nodules and Granulomas
Art Rendering of an Inflamed Bronchiole in Follicular Bronchiolitis
The image depicts a bronchial wall rendered in red, symbolizing inflammation, with blue cellular infiltrates representing lymphocytes and a focal nodule of lymphoid proliferation—all while maintaining an uncompromised lumen. This correlates would be a centrilobular nodule seen on CT.
– Ashley Davidoff, MD | TheCommonvein.net lungs-0766-01- lo res follicular bronchiolitis)

Infiltration Around and In Small Airways

Ill Defined Centrilobular Nodules and Subpleural Nodules
The infiltration of lymphocytes, histiocytes and plasma cells along the lymphatics of the lungs, can sometimes result in ill defined nodules that may be centrilobular or subpleural in location
Ashley Davidoff MD TheCommonVein.net
32645a06L
Small Airway Fibrosis and Luminal Narrowing or Obstruction 
The diagram shows fibrotic changes around and within the small airways including the terminal bronchiole, respiratory bronchiole and the alveolar duct.  In this instance the increase density from the fibrotic tissue would result in ground glass changes in the parenchyma and solid centrilobular nodules.  Obstruction of the small airways  would result in air trapping.
Ashley Davidoff MD TheCommonVein.net lungs-0778
Small Airway Fibrosis
The diagram shows fibrotic changes around the small airways including the terminal bronchiole, respiratory bronchiole and the alveolar duct.  In this instance the increase density from the fibrotic tissue would result in ground glass changes in the parenchyma and ground glass centrilobular nodules.  Since the airways are patent there would be no air trapping.
Ashley Davidoff MD TheCommonVein.net lungs-0777
Specific Disease CT Findings Associated Findings
Sarcoidosis Upper lobes; perilymphatic nodules; mediastinal and hilar lymphadenopathy; fibrosis in chronic cases Bilateral hilar lymphadenopathy; lung fibrosis; elevated ACE levels
Hypersensitivity pneumonitis Mid to upper lobes; centrilobular nodules; ground-glass opacities; mosaic attenuation Air trapping on expiratory imaging; history of antigen exposure
Granulomatosis with polyangiitis (Wegener’s) Upper and lower lobes; cavitary nodules; irregular margins; adjacent ground-glass opacity; central necrosis Tracheobronchial thickening; nasal and sinus involvement; renal disease
Tuberculosis Upper lobes; cavitary lesions; tree-in-bud nodules; lymphadenopathy Night sweats; hemoptysis; weight loss; positive PPD or IGRA
Bronchogenic carcinoma Upper and lower lobes; spiculated mass; airway obstruction; post-obstructive atelectasis Mediastinal lymphadenopathy; pleural effusion; distant metastases
Infectious causes (fungal, mycobacterial) Variable lobar involvement; tree-in-bud nodules; cavitation; consolidation Immune-compromised status; fever; history of exposure

Other Causes

Category Specific Disease CT Findings Associated Findings
Inflammation and Immune Disorders Eosinophilic pneumonia Peripheral and upper lobe predominance; ground-glass opacities; consolidation; crazy-paving pattern Peripheral eosinophilia; history of asthma or allergic disease
Neoplasm (Malignant and Benign) Carcinoid tumor Central or peripheral location; well-defined nodule; possible calcification; bronchial narrowing Endobronchial mass; post-obstructive changes; rarely metastasizes
Mechanical Trauma Foreign body aspiration Unilateral hyperinflation; foreign body in airway; post-obstructive collapse Cough, stridor, recurrent pneumonia; history of aspiration
Metabolic Amyloidosis Upper and lower lobes; nodular opacities; calcifications; airway involvement Tracheobronchial thickening; systemic involvement
Circulatory Pulmonary infarction Peripheral wedge-shaped opacity; pleural-based infarction; ground-glass halo History of deep vein thrombosis; lower extremity swelling
Immune IgG4-related disease Peribronchovascular thickening; nodules; mediastinal lymphadenopathy Elevated IgG4 levels; systemic involvement (pancreas, kidneys)
Infiltrative Langerhans cell histiocytosis (LCH) Upper lobe cystic changes; nodules; interstitial thickening Cystic lung changes; smoking history; systemic involvement
Inherited and Congenital Cystic fibrosis Upper lobe bronchiectasis; mucous plugging; hyperinflation Recurrent infections; pancreatic insufficiency
Iatrogenic Radiation-induced lung injury Peripheral ground-glass opacities; fibrosis; consolidation History of radiation therapy; fibrosis progression over time
Idiopathic Idiopathic nodular bronchiolitis Centrilobular nodules; tree-in-bud opacities; airway thickening Non-specific inflammation; chronic airway symptoms
Functional No known direct functional disorders No known direct imaging findings No relevant associated findings
Psychiatric and Psychological Factitious disorder (self-induced inhalation of irritants) Non-specific airway changes; evidence of inhaled foreign materials History of psychiatric illness; presence of inhaled irritants
Art Rendering of an Inflamed Bronchiole in Follicular Bronchiolitis
The image depicts a bronchial wall rendered in red, symbolizing inflammation, with blue cellular infiltrates representing lymphocytes and a focal nodule of lymphoid proliferation that compromises the bronchial lumen. This correlates with a centrilobular nodule seen on CT.
– Ashley Davidoff, MD | TheCommonvein.net (lungs-0729-01)
Art Rendering of an Inflamed Bronchiole in Follicular Bronchiolitis with Small Airway Obstruction
The image depicts a bronchial wall rendered in red, symbolizing significant thickening and inflammation, with blue cellular infiltrates representing lymphocytes, and a focal nodule of lymphoid proliferation that obstructs the bronchial lumen. This correlates with a centrilobular nodule seen on CT.
– Ashley Davidoff, MD | TheCommonvein.net (lungs-0730 -lo-res res follicular bronchiolitis)
Art Rendering of an Inflamed Bronchiole in Follicular Bronchiolitis with Small Airway Obstruction
The image depicts a bronchial wall rendered in red, symbolizing thickening and inflammation, with blue cellular infiltrates representing lymphocytes, and a focal nodule of lymphoid proliferation that obstructs the bronchial lumen. This correlates with a centrilobular nodule seen on CT.
– Ashley Davidoff, MD | TheCommonvein.net
lungs-0731 -lo res follicular bronchiolitis

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