Angiosarcoma of the right atrium presenting as collapse.

Pericardial effusion may originate from a wide variety of underlying pathology. Primary cardiac malignancy should always be considered as a rare underlying cause. Angiosarcoma is the most common cardiac malignancy, which often arises as a mass in the right atrium. We describe a young patient with collapse due to pericardial effusion caused by a primary cardiac angiosarcoma. The case is an example of the difficulties and dilemmas which may be encountered in assessing the diagnosis of cardiac angiosarcoma.