Atypical sarcoidosis diagnosed using endobronchial ultrasound-guided mediastinal lymph node biopsy with fine biopsy forceps: Two case reports.

BACKGROUND

To evaluate the diagnostic utility of endobronchial ultrasound (EBUS)-guided mediastinal lymph node fenestration biopsy in atypical sarcoidosis using fine biopsy forceps [i.e., EBUS-transbronchial forceps biopsy (TBFB)].

CASE SUMMARY: In this case series, two atypical sarcoidosis cases admitted in 2024 were retrospectively analyzed, both of whom lacked classical clinical manifestations. After chest computed tomography/positron emission tomography-computed tomography imaging and serum angiotensin-converting enzyme testing, EBUS-transbronchial needle aspiration was performed using a 21-G needle. Subsequently, tissue sampling was performed at the enlarged puncture site by means of a 1.2-mm fine biopsy forceps. At the same time, bronchoalveolar lavage fluid lymphocyte subset analysis was conducted.

CONCLUSION

Both cases demonstrated non-caseating granulomatous inflammation on histopathology, elevated serum angiotensin-converting enzyme levels, and markedly increased CD4/CD8 ratios in bronchoalveolar lavage fluid. Case 1 was observed after confirmation of stage II sarcoidosis, whereas case 2 required glucocorticoid therapy due to the involvement of multiple systems. EBUS-TBFB can be used to make a definitive pathological diagnosis. For radiologically atypical sarcoidosis, EBUS-TBFB improves diagnostic accuracy by obtaining larger histological samples, thereby addressing the limitations of transbronchial needle aspiration cytology. This approach significantly improves differential diagnostic efficacy and holds substantial clinical relevance for broader adoption.