Role of endoscopic ultrasound in undiagnosed pleural effusion

BACKGROUND AND OBJECTIVES: Thoracocentesis is the first diagnostic procedure for pleural effusion (PE). If diagnosis after thoracocentesis remains uncertain, pleural biopsy either computed tomography (CT)/ultrasonography (USG)-guided or thoracoscopy is required for definitive diagnosis. Overall, access to thoracoscopy is limited in many parts of the world as significant resources and expertise are required. We present the data about evaluation of undiagnosed PE by endoscopic ultrasound (EUS)-guided pleural aspiration or fine needle aspiration cytology (FNAC) of the lymph nodes/pleural deposits. This is first case series regarding EUS-guided FNAC of pleural deposits. METHODS: During 2 years, 11 patients of undiagnosed PE were evaluated by EUS. Aspiration of PE was done if fluid sampling was required and EUS-FNA with rapid on-site evaluation (ROSE) was done if FNAC from PE deposit or lymph node was required. RESULTS: Seven patients had right sided and four had left PE. Three cases had unsuccessful attempts/complications at US-guided aspiration. A single pass was successful in diagnostic aspiration in these cases and the aspirated fluid was suggestive of tuberculosis. The remaining eight cases had nondiagnostic aspiration and FNAC with ROSE (average two passes) was done from mediastinal lymphadenopathy or pleural deposits. Four cases with mediastinal lymphadenopathy had granulomatous lesions. Four cases with pleural deposits had malignancy. In this series, EUS was selected as the last diagnostic option for three indications: nontappable PE (3 cases), PE with mediastinal nodes (4 cases) and PE with pleural deposits (4 cases). CONCLUSION: EUS-guided imaging introduces a totally different path/technique of imaging for inspection of the pleural space. EUS-FNA can be performed as safe procedure in undiagnosed PE. At present, it appears that EUS-guided evaluation is an alternative modality for the evaluation of undiagnosed PE, in the cases who are unfit for thoracoscopy and as an alternative or adjunct to USG/CT-guided aspiration or biopsy.