Background: The diagnosis of sarcoidosis requires both compatible clinical features and pathologic findings as a means to exclude other differential diagnoses. The utility of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for diagnosis of sarcoidosis has been reported, although its indication remains unclear for cases of suspicious sarcoidosis. To clarify the role of EBUS-TBNA for the diagnosis of sarcoidosis, we compared three diagnostic modalities: EBUS-TBNA, transbronchial lung biopsy (TBLB) and bronchoalveolar lavage fluid analysis (BAL).
Methods: Thirty-eight patients with suspicious sarcoidosis who had enlarged hilar and/or mediastinal lymph nodes on chest CT were retrospectively reviewed. Patients with malignancies or prior established diagnosis of sarcoidosis were excluded. BAL was initially performed followed by TBLB and finally EBUS-TBNA at the same setting. Microbacterial examinations were also performed from all samples.
Results: Pathological findings compatible with sarcoidosis were obtained in 32 patients. The remaining 6 patients were diagnosed as one case each of chronic eosinophilic pneumonia, atypical mycobacterial infection and tuberculosis, and the remaining three were pathologically indefinite cases. Clinically, 35 patients were diagnosed with sarcoidosis. The diagnostic accuracy of sarcoidosis was significantly better by EBUS-TBNA (91.4%, p<0.001) compared to the other two modalities. According to chest roentgenogram classifications, there were 31 stage I patients and 4 stage II patients. For stage I patients, EBUS-TBNA was significantly better (90.3%, p<0.001), but each modality showed 100% accuracy for stage II patients.
Conclusion: It is recommended that EBUS-TBNA is added to the conventional diagnostic modalities for patients with suspicious stage I sarcoidosis on chest roentgenogram.