Endosonography-guided fine needle aspiration cytology of intra-abdominal lymph nodes with unknown primary in a tuberculosis endemic region.

Background And Aim: Intra-abdominal lymphadenopathy poses a diagnostic and management challenge in highly endemic regions for tuberculosis. Opting for empirical anti-tuberculosis treatment raises the risk of wrong or delayed treatment. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is the procedure of choice for tissue acquisition from peri-luminal lymph nodes. We studied the utility of EUS-FNA in evaluating intra-abdominal lymph nodes of unknown etiology, in the setting of high endemicity of tuberculosis.

Methods: Consecutive patients with intra-abdominal lymph nodes of unknown etiology underwent EUS-FNA using a 22-gauge needle. Final diagnosis was made on surgical histology or on 6-months follow-up. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic yield were calculated.

Results: Sixty-six patients were included. Final diagnoses were tuberculosis, 35 (53%); metastatic adenocarcinoma, 11 (16.7%); lymphoma, three (4.5%); carcinoid, one (1.5%) and reactive nodes, 16 (24.2%). EUS-FNA provided a diagnosis in 61 patients (92.4%). Sensitivity, specificity, PPV and NPV for diagnosing tuberculosis via EUS-FNA were 97.1%, 100%, 100% and 96.9%, respectively. In 10 (15.2%) patients receiving empirical anti-tuberculosis treatment, the final diagnoses were metastatic adenocarcinoma (5), lymphoma (2), carcinoid (1) and reactive adenopathy (2).

Conclusion: Despite being in a highly endemic area, almost half of the patients studied have a non-tuberculosis etiology. EUS-FNA is a safe and accurate procedure for establishing the diagnosis of unexplained intra-abdominal lymphadenopathy.