Cytomorphological diagnosis of sarcoidosis using EBUS-TBNA in a tuberculosis-endemic region

Sarcoidosis, a granulomatous inflammatory disease, exhibits diverse clinical manifestations, often affecting multiple organs. Diagnostic challenges arise due to its similarities with tuberculosis, particularly in high-burden areas. Differentiating between the two relies on clinical judgment, laboratory tests, imaging, and invasive procedures. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has emerged as a valuable diagnostic tool, enhancing both accuracy and patient care.

This study enrolled 279 suspected sarcoidosis cases, evaluated via EBUS-TBNA between November 2022 and August 2023. The inclusion criteria comprised intrathoracic lymphadenopathy on CT, with subsequent diagnoses of either sarcoidosis or tuberculosis. Clinical, radiological, and laboratory assessments, along with EBUS-TBNA, were conducted. Cytopathological analysis focused on the presence of granulomas, histiocytic clusters, lymphocyte depletion, and necrosis, which aided in diagnosis. Statistical analysis was conducted using SPSS software to evaluate sensitivity, specificity, and predictive values.

Out of 279 patients, 178 were diagnosed with sarcoidosis and 90 with tuberculosis. Adequate TBNA samples were obtained in 240 cases, predominantly from male patients. Negative tuberculin skin tests and negative culture studies were significant findings in the sarcoidosis cases (p<0.0001). Echotexture and necrosis were distinguishing features of tuberculosis, while granulomas and histiocyte patterns varied. The sensitivity and specificity for diagnosing sarcoidosis via cytomorphology were notable, particularly when combined with negative microbiological findings.

Cytomorphological analysis via EBUS-TBNA significantly aids in the diagnosis of sarcoidosis, despite overlapping features with tuberculosis. The absence of necrosis and distinctive granuloma characteristics contribute to its high sensitivity and specificity. Radiological correlations and microbiological findings further enhance diagnostic accuracy. This study underscores the importance of comprehensive evaluation in intrathoracic lymphadenopathies, highlighting the pivotal role of EBUS-TBNA in tuberculosis-endemic regions.