Confocal Laser Endomicroscopy Assisted Ultrasound Guided Pleural Biopsy

Inclusion Criteria: * Adult patients with exudative pleural effusion of unknown origin * Patients with negative pleural fluid cytology results * Patients diagnosed with a probable malignant pleural effusion but without a definite diagnosis and requiring further pathological evaluation * Patients who are fully informed of the purpose and method of the study, agree to participate in the study, and sign an informed consent form Exclusion Criteria: * Inability or refusal to undergo UGBx * Patients with any contraindications for pleural biopsy