A 16-year-old student presented with a 4-week history of progressive shortness of breath, loss of appetite, and occasional blood-tinged sputum. The chest X-ray revealed massive right-sided pleural effusion with cardiomegaly. An echocardiogram revealed a large pericardial mass with massive pericardial effusion. Subsequent computed tomography of the thorax revealed a large heterogeneous mass in the right lung with extension into the pericardium. Lung biopsy revealed primitive neuroectodermal tumor (PNET) with small round blue cells, Homer-Wright rosettes, and CD99 positivity. We discuss pericardial metastases of PNET and its implication in this patient.