Abstract
Lung cancer is the number one cause of cancer-related deaths in the United States. Involvement of pericardium occurs once cancer has progressed to stage IV which can cause massive effusion in the pericardial sac. This can lead to cardiac tamponade which can be fatal very quickly if untreated. The following is a two patient case series in which both patients presented with large pericardial effusion. The first patient sought medical attention due to new onset palpitations and was found to have hemorrhagic pericardial effusion and pulmonary embolism (PE). The second patient presented with shortness of breath. Investigations revealed that she had pericardial and pleural effusions along with multiple metastases throughout the body. Both patients ended up with a diagnosis of non-small cell lung cancer (NSCLC) with BRAF mutation. One patient had V600E mutation; other patient had a variant p.D594N mutation. Both patients also had expression of PD-L1.