Pulmonary sarcoidosis is histologically characterized by which feature?

• A. Noncaseating granulomas
• B. Caseating granulomas
• C. Alveolar edema with eosinophils
• D. Eosinophilic infiltration of airways

Answer: (A)

Noncaseating granulomatous inflammation is the histologic hallmark of pulmonary sarcoidosis. In the lungs, these consist of tightly clustered epithelioid macrophages with multinucleated giant cells, all surrounded by a rim of lymphocytes. Importantly, there is no central necrosis—the “noncaseating” aspect distinguishes sarcoidosis from conditions like tuberculosis, where granulomas typically show caseation. This pattern reflects a granulomatous immune response rather than edema or eosinophilic inflammation. Alveolar edema with eosinophils or eosinophilic airway infiltration points to other processes such as eosinophilic pneumonias or allergic airway diseases, not sarcoidosis.