Primary Lung Adenocarcinoma Presenting with Life-Threatening Cardiac Tamponade: A Case Report

Background: Malignant cardiac tamponade is a rare but critical complication of metastatic cancers, often arising from lung or breast primaries. It results from pericardial infiltration by malignant cells, leading to fluid accumulation and hemodynamic compromise. Case Presentation: We describe a 78-year-old woman with a history of chronic respiratory illness and multiple comorbidities who presented with worsening dyspnea and respiratory failure. Imaging revealed a right upper lobe mass and a large pericardial effusion with signs of tamponade. An echocardiogram confirmed tamponade physiology with right ventricular collapse and a swinging heart. Emergent pericardiocentesis yielded 800 mL of hemorrhagic fluid, which was cytologically positive for metastatic adenocarcinoma, likely of pulmonary origin. Despite temporary symptom relief, the effusion recurred. The patient opted for palliative surgical creation of a pericardial window and placement of an indwelling pleural catheter to manage recurrent symptoms. Conclusion: This case highlights the importance of recognizing malignant cardiac tamponade as a potential early manifestation of metastatic lung cancer. Prompt diagnosis and drainage are crucial for stabilizing patients. In advanced malignancies, palliative interventions such as pericardial window formation can significantly improve quality of life and align with patient-centered goals of care