[Invasive thymoma with pericardial tamponade as initial manifestation].

A 68-year-old man presented to another hospital with progressive shortness of breath, dry cough, and systemic edema. A chest X-ray, echocardiogram, and chest CT showed a mediastinal mass and massive pericardial effusion. His symptoms improved after the treatment for heart failure. The pericardial effusion was bloody. In that, malignant cell wasn't proved. Thoracotomy was performed to diagnose the mediastinal tumor and to extirpate it. Pathological diagnosis after operation was thymoma with direct invasion to pericardium and tunica externa of aorta. Thymomas are routinely asymptomatic for prolonged periods of time. Symptomatic pericardial tamponade as initial manifestation due to a thymoma with a massive pericardial effusion is uncommon.