Ultrasound guided fine needle aspiration biopsy in mediastinal tuberculosis

SETTING: Diagnosis of mediastinal tuberculosis (TB) is difficult due to nan -specific clinical features and lack of characteristic radiographic feature s. Histopathological confirmation has often required computed tomography gu ided fine needle aspiration biopsy (FNAB) or even invasive procedures such as mediastinoscopy or open/ surgical biopsy. FNAB under ultrasound (US) gui dance can also be performed in this clinical setting. OBJECTIVE: To define the role of percutaneous US guided FNAB in the diagnos is of mediastinal tuberculosis. DESIGN: Twenty-six patients with a proven diagnosis of mediastinal TB forme d the studs group. Chest radiographs and sputum examination were negative. FNAB was performed via suprasternal (n = 20) and parasternal (n = 6) route under sonographic guidance using 22G spinal needle. Aspirates were consider ed positive for TB when epithelioid cell granuloma with caseation necrosis and/or the presence of Mycobacterium tuberculosis by acid-fast bacilli (AFB ) or culture was demonstrated, indeterminate when epithelioid cell granulom as were seen but without caseation necrosis or AFB, and negative when aspir ate contained non-representative material. RESULTS: A total of 30 biopsies were performed in the 26 patients, includin g repeat biopsy and biopsy of different sites in two patients each. FNAB wa s positive for TB in 20 of the 26 patients. In four, AFB were demonstrated, and in seven culture was positive for M. tuberculosis; in the remaining si x patients, cytologic diagnosis was indeterminate in four and negative in t wo. No procedure related complications were noted. CONCLUSION: Ultrasound guided FNAB is a safe, effective technique in the di agnosis of mediastinal TB.