Centrilobular lung nodules

Centrilobular lung nodules refer to a HRCT chest imaging descriptor for small 5-10 mm lung nodules which are anatomically located centrally within secondary pulmonary lobules. The term is applied on the basis of location of the nodule and not its morphology, that is they may be well-defined or poorly-defined ground glass in appearance. If extremely small they are termed centrilobular micronodules.

Pathology

Etiology

Centrilobular nodules can be observed in a wide variety of lung pathology. They are usually seen with bronchiolitis (i.e. with bronchiolar or peribronchiolar abnormalities). Specific conditions include:

• bronchiolitides
  • obliterative bronchiolitis ³
• infection with endobronchial spread
  • airway spread of tuberculosis
  • airway spread of non-tuberculous mycobacterial infection
  • airway invasive aspergillosis ³
• lung adenocarcinoma with airway spread
• non-fibrosing hypersensitivity pneumonitis ¹
• respiratory bronchiolitis interstitial lung disease (RB-ILD) ⁵
• pulmonary vasculitides
  • eosinophilic granulomatosis with polyangiitis (EGPA) ⁴

When centrilobular nodules are interspersed with linear and branching densities, it is then termed a tree-in-bud pattern.

Radiographic features

CT

HRCT chest

On HRCT chest, centrilobular nodules are typically found around the small airways and spare the subpleural surfaces. They are typically at least 5-10 mm away from the pleural surfaces ^ref.

• small pulmonary nodules: HRCT chest approach

See also

• lung nodules
  • ground glass nodules
  • calcified lung nodules
  • perilymphatic nodules
    • perifissural pulmonary nodules
• secondary pulmonary lobule