Diagnosis of pulmonary sarcoidosis

To summarize and highlight recent advances in the field of the diagnosis of pulmonary sarcoidosis.

Several techniques have emerged as important tools in the context of a clinical and radiological situation compatible with pulmonary sarcoidosis. Among them, computed tomography (CT) scan can not only exhibit characteristic imaging, but also contribute to an increased yield of tissue sampling through transbronchial biopsies. CT is also essential to the detection of mediastinal lymphadenopathy as potential targets of endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA). The latter is a well-tolerated and highly sensitive procedure which might become the first-line diagnostic tool in sarcoid patients with hilar or mediastinal lymph nodes. 18F deoxy-fluoro-glucose (18F-FDG) PET has a remarkable sensitivity in the detection of occult sites of the disease and a high value in guiding biopsy to these active sites. A combined imaging modality using both F-FDG PET and CT scan, more sensitive than PET alone, is now the standard of care in patients requiring histological sampling of active lesions.

The finding of noncaseating granulomas remains crucial to the diagnosis of sarcoidosis. The methods described here markedly enhance the diagnostic yield of tissue sampling along with low risks of complications.