Alveolar Sarcoid

General Considerations

• Least common manifestation of sarcoid in the lungs (2%)
• Several large airspace “masses” frequently with air bronchograms
• Occurs when granulomas become confluent and compress airspaces

Clinical Findings

• May have an abrupt onset and may change rapidly

Imaging Findings

• Bilateral, multifocal, ill-defined nodules mimicking airspace disease
• May be peripheral in lung, like pulmonary infiltrates with eosinophilia
• “Masses” with air bronchograms
  • May very rarely have cavitation
• Gallium 67 will be taken up in sarcoid and may show extranodal sites of involvement, but is not specific

Differential Diagnosis

• Alveolar cell carcinoma
• Lymphoma
• Alveolar proteinosis
• Multifocal pneumonia

Treatment

• Alveolar sarcoid tends to improve with or without steroids

Complications

• High risk for spontaneous pneumothorax

Prognosis

• The “airspace” component of pulmonary sarcoid invariably disappears
• Reticulonodular disease may remain

Alveolar Sarcoid. Frontal chest radiograph at left demonstrates multiple, scattered mass-like densities with irregular margins. The disease affects primarily the periphery of the lungs. A CT scan of another patient with alveolar sarcoid (right) shows multiple patchy densities with air bronchograms (black arrows).
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