This document provides an overview of malignant pleural effusion (MPE), including its causes, epidemiology, pathophysiology, clinical presentation, diagnostic findings, treatment options, nursing management, and nursing diagnoses. MPE is an abnormal collection of fluid in the pleural space due to malignant cells. Lung cancer and breast cancer account for 50-65% of cases. Treatment is palliative and includes thoracentesis, chest tube drainage with pleurodesis, thoracoscopy, or indwelling pleural catheter placement. Nursing focuses on symptom management, respiratory assessments, positioning, breathing exercises, and preparing patients for procedures.