The Role of Thoracoscopy in the Diagnosis of Pleural Effusion of Unknown Origin

BACKGROUND AND OBJECTIVE: Video-assisted thoracoscopic surgery is preferred over conventional methods, such as pleural biopsy, in the diagnosis and treatment of patients with pleural effusion. Considering that Imam Khomeini Hospital is facing a large volume of patients with pleural effusion of unknown origin referred from other centers, the present study was conducted to investigate the role of thoracoscopy in the diagnosis of pleural effusion of unknown origin. METHODS: In this prospective study, 31 patients with pleural effusion of unknown origin, whose disease was not diagnosed using conventional methods such as imaging, thoracentesis or pleural biopsy, were treated with video-assisted thoracoscopic surgery (VATS) at Imam Khomeini Hospital in Urmia. FINDINGS: The most common symptoms were dyspnea in 18 patients followed by chest pain in 8 patients and cough in 5 patients. Histological findings reported cancer in 19 patients, pleuritic in 10 patients and tuberculosis in 2 patients. Among the patients with malignant pleural effusion, the most common causes were metastatic carcinoma (42.1%) adenocarcinoma (26.3%) and mesothelioma (7.5%). In general, VATS was unable to definitively diagnose the disease in 5 patients. The diagnostic function of VATS was 83.9% in patients with pleural effusion of unknown origin (CI-95%= 71–96.8).   CONCLUSION: The results showed that thoracoscopy along with imaging can be helpful in detecting pleural effusion with unknown origin.