What are the causes of peribronchial ground-glass opacities (GGO)?

Causes of Peribronchial Ground-Glass Opacities

Peribronchial ground-glass opacities (GGO) most commonly indicate organizing pneumonia (OP), hypersensitivity pneumonitis (HP), or drug-related pneumonitis, with the peribronchovascular distribution being a key distinguishing feature from other GGO patterns. 1

Primary Causes by Distribution Pattern

Organizing Pneumonia Pattern

• Multifocal patchy alveolar opacities with peribronchovascular distribution are the hallmark of organizing pneumonia, which can be idiopathic (BOOP) or secondary to drugs, infection, or connective tissue disease 1
• The peribronchovascular pattern may demonstrate a reversed halo sign and often occurs with immune checkpoint inhibitors, EGFR-TKIs, and mTOR inhibitors 1
• This pattern typically shows patchy consolidation extending along bronchovascular bundles rather than purely peripheral distribution 1

Hypersensitivity Pneumonitis

• Poorly defined centrilobular nodules with bilateral GGO in a peribronchovascular distribution characterize HP, particularly in the subacute phase 1
• The peribronchovascular distribution in HP reflects the bronchiolocentric nature of the inflammatory process 1
• Air trapping on expiratory images with centrilobular nodules has 100% specificity for HP when present together 2

Drug-Related Pneumonitis

• Peribronchovascular GGO occurs with multiple drug reaction patterns, including NSIP-like and OP-like presentations from molecular targeting agents and immune checkpoint inhibitors 1
• Fibrotic NSIP pattern shows peribronchovascular predominance with fine reticulation and traction bronchiectasis 1

Pulmonary Veno-Occlusive Disease (PVOD)

• Centrilobular (peribronchial) distribution of GGO is significantly more frequent in PVOD compared to idiopathic pulmonary arterial hypertension (p = 0.03) 1
• The association of centrilobular GGO with septal lines and mediastinal adenopathy has 100% specificity for PVOD in patients with pulmonary hypertension 1
• This represents postcapillary venous obstruction causing interstitial edema in a characteristic peribronchial pattern 1

Secondary Considerations

Infectious Causes

• Viral pneumonias (influenza, COVID-19, CMV) can present with peribronchial GGO, though typically show more diffuse or patchy random distribution 3
• Atypical infections may demonstrate peribronchovascular infiltration patterns 4

Pulmonary Edema

• Hydrostatic edema causes expansion of connective tissue space around conducting airways and vessels, creating peribronchovascular haziness 4
• This is the most common cause of widespread GGO overall (56% of cases), but the peribronchovascular pattern is less specific than other distributions 2

Critical Diagnostic Distinctions

When evaluating peribronchial GGO, look for these specific associated findings:

• Septal thickening + pleural effusions → suggests hydrostatic edema (91% specificity) 2
• Centrilobular nodules + air trapping → indicates HP (100% specificity) 2
• Septal lines + adenopathy + centrilobular GGO → highly specific for PVOD (100% specificity) 1
• Reversed halo sign → suggests organizing pneumonia or fungal infection 1, 5

Common Pitfall

Do not confuse peribronchovascular GGO with mosaic attenuation from small airway disease - check vessel caliber in areas of decreased attenuation and obtain expiratory images to identify air trapping, which indicates primary airway pathology rather than infiltrative disease 6, 1

Clinical Context Matters

• Inpatient setting: Pulmonary edema accounts for 75% of GGO cases 2
• Outpatient setting: Interstitial lung disease (particularly HP and connective tissue disease-related ILD) accounts for 49% of cases 2
• Immunocompromised patients: Consider opportunistic infection (24% of cases) alongside edema 2
• Recent drug exposure: Drug-related pneumonitis should be high on the differential, particularly with newer targeted therapies 1