Endoscopic ultrasound-guided fine-needle aspiration cytology in the evaluation of suspected tuberculosis in patients with isolated mediastinal lymphadenopathy

Background and study aims: Patients with suspected tuberculosis without pulmonary lesions and with mediastinal lymphadenopathy often pose a diagnostic challenge. Endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) cytology is an established modality to evaluate mediastinal and abdominal lesions. The aim of the present study was to evaluate the role of EUS-FNA in isolated mediastinal lymphadenopathy in patients suspected of having tuberculosis. Methods: Consecutive patients suspected of having tuberculosis with isolated mediastinal lymphadenopathy were included in a prospective study. Mediastinal lymphadenopathy was diagnosed on a contrast-enhanced computed tomography scan of the chest. Patients with concomitant lung parenchymal lesions were excluded. Previous attempts to diagnose the etiology of lymphadenopathy had failed in 69% of patients. EUS-FNA was performed on an outpatient basis under conscious sedation. The sensitivity, specificity, and diagnostic accuracy of EUS-FNA were calculated. Results: A total of 60 consecutive patients (mean age 39.8 years, 58% males) with mediastinal lymphadenopathy were included. EUS confirmed the presence of mediastinal lymph nodes ranging in size from 8 mm to 40 mm (mean 26 mm) in all patients. EUS-FNA provided an adequate tissue sample in 54 patients during the first examination and repeat EUS-FNA was necessary in six patients. A final diagnosis was obtained by EUS-FNA in 42 patients (tuberculosis in 32, sarcoidosis in six, and Hodgkin's disease in four patients). An additional 14 patients were treated for tuberculosis based on EUS-FNA and clinical features. Mediastinoscopy was required for diagnosis in the remaining four patients. EUS-FNA had an overall diagnostic yield of 93%, sensitivity of 71%, specificity of 100%, and positive predictive value of 100%. Conclusion: EUS-FNA is an accurate, safe, and minimally invasive modality for evaluating isolated mediastinal lymphadenopathy in patients suspected of having tuberculosis in an endemic area with a high prevalence of tuberculosis.