Which combination of findings is most characteristic of sarcoidosis?

• A. Cavitations on chest X-ray with caseating granulomas.
• B. Ground-glass opacities and eosinophils.
• C. Hilar lymphadenopathy on chest X-ray; elevated ACE; and non-caseating granulomas on tissue biopsy.
• D. Pleural effusion with bacterial infection.

Answer: (C)

Sarcoidosis is a multisystem granulomatous disease in which the hallmark is noncaseating granulomas formed by activated macrophages and T cells. In the lungs, this often shows up as bilateral hilar lymphadenopathy on chest imaging, especially in earlier stages. Elevated serum ACE levels occur because granuloma macrophages produce ACE, supporting the diagnosis though not being perfectly specific. The definitive clue comes from tissue biopsy, which typically reveals noncaseating granulomas without caseation.

This combination—hilar lymphadenopathy on chest X-ray, elevated ACE, and noncaseating granulomas on biopsy—best captures the characteristic pattern of sarcoidosis. Cavities with caseating granulomas would suggest tuberculosis or fungal infection; pleural effusion with bacterial infection points away from sarcoidosis; and ground-glass opacities with eosinophils are more consistent with other conditions like eosinophilic pneumonia or hypersensitivity processes.