Malignant pericardial effusion not diagnosed by pericardial fluid and biopsy: importance of CT scan.

A 47-year-old female came to the emergency room due to dyspnea for 1 month. Initial chest X-ray showed enlargement of the cardiac silhouette. Emergent echocardiogram demonstrated large amount of pericardial effusion. Pericardiostomy with pericardial biopsy was performed. The etiology of large amount of hemorrhagic pericardial effusion could not be confirmed even by aggressive analysis of pericardial fluid and pericardial biopsy. CT scan of the mediastinum was performed. Percutaneous fine needle aspiration biopsy demonstrated thymic carcinoma with focal squamous differentiation. When the analysis of pericardial fluid and pericardial biopsy cannot reveal the etiology of hemorrhagic pericardial effusion, CT scan should be performed.