Primary cardiac malignancy is very rare. The most common malignant cardiac tumours are angiosarcomas. Their diagnosis is sometimes difficult because of their nonspecific clinical presentation. Two cases of primary cardiac angiosarcomas that were not diagnosed clinically due to unusual presentations are presented. Pathological diagnosis was missed in one case because of lack of thorough examination and sampling of submitted specimens. Cardiac symptoms in a patient with primary angiosarcoma of the heart may not always be present. In the presence of unusual serious systemic symptomatology, such as multisystemic hemorrhagic phenomena, disseminated infiltrative pulmonary lesions or peripheral tumour associated with subtle heart abnormalities, the possibility of cardiac angiosarcoma should be included in the differential diagnosis.