Diagnosis of malignant pleural effusion using thoracoscopy combined with confocal endomicroscopy: a case report

Thoracoscopy is widely used for the diagnosis and management of pleural diseases. This technique is valuable because it enables direct visualization of the pleural cavity surface and pathologic biopsy sampling of lesions. However, it is limited in detecting early-stage pleural lesions, carrying a considerable risk of misdiagnosis or missed diagnosis, which may delay treatment and ultimately compromise patient poutcome. Confocal laser endomicroscopy (CLE) is an emerging in vivo microscopy technique that can be integrated with traditional thoracoscopy platforms, providing real-time in vivo observation of pleural cellular and histologic features. This technology helps identify early microscopic lesions and guide thoracoscopic pleural biopsies, thereby reducing the risk of misdiagnosis and missed dignosis associated with conventional thoracoscopic biopsies. In this case report, we present a patient with unexplained pleural effusion and elevated tumor markers, for whom conventional thoracoscopy revealed no significant pleural abnormalities. Subsequently, under thoracoscopic guidance, we performed a CLE-based microscopic scan of the pleura, which revealed clusters of darkly pigmented cells with significant atypia. Targeted biopsy of this area under thoracoscopy confirmed a final pathologic diagnosis of right upper lung adenocarcinoma.