Diagnostic yield of transbronchial needle aspiration for lymphoma

Background. Transbronchial needle aspiration (TBNA) is a minimally invasive bronchoscopic technique that is cost-effective and safe for diagnosing mediastinal and hilar adenopathy in lung cancer, other malignancies, sarcoidosis and infectious processes such as tuberculosis. Few studies have analysed the sensitivity, specificity and predictive values of TBNA for diagnosing lymphoma. Objective. To evaluate the diagnostic yield of TBNA for diagnosing mediastinal and hilar adenopathy in suspected lymphoma. Methods. We performed a retrospective analysis of collected data of patients with mediastinal and hilar adenopathy adjacent to the tracheobronchial tree detected by thoracic computed tomography, who underwent TBNA at Tygerberg Hospital between July 2010 and June 2013. We included 25 patients with suspected or proven lymphoma. Histology was used as the gold standard. Results. Adequate samples for cytological evaluation were obtained for 22 (88%) patients. Cytological diagnosis was possible for 8 (32%). For 17 (68%) who could not be diagnosed by TBNA alone, histology provided final diagnosis. Rapid on-site examination (ROSE) was performed in 23 (92%). In 17/23 (74%) cases, these had similar results to formal cytology. Only 4 (16%) had flow cytometry requested. Twelve (48%) had lymphoma confirmed on histology. TBNA cytology had 100% specificity and positive predictive value for suspicion of lymphoma. Sensitivity was 33% and negative predictive value 62%. Conclusion. TBNA is an appropriate first-line diagnostic procedure in evaluating mediastinal and hilar lymphadenopathy in suspected lymphoma. Biopsy should be the immediate second-line procedure when ROSE/cytology is suspicious of lymphoma or shows atypical cells. Patients with negative TBNA cytology, but high clinical or radiological suspicion of lymphoma, should be further investigated.