Primary cardiac angiosarcoma masquerading as intracardiac thrombus.

A 49-year-old man with a recent history of atrial tachycardia and intracardiac thrombus presented to the emergency department with melena and cardiac tamponade. Physical examination was notable for a vascular mass at the right lower gingival sulcus and a right chest wall nodule. Enteroscopy revealed a target lesion with friable ulcer in the gastric body. Cardiac MRI revealed a large right atrial mass, previously thought to represent thrombus. The patient was ultimately diagnosed with primary cardiac angiosarcoma (PCAS) by histopathology of gingival, gastric and subcutaneous lesions. This case illustrates the significant morbidity and mortality resulting from aggressive local invasion and growth of PCAS, as well as the challenge of differentiating between primary thrombosis and vascular malignancy. Misdiagnosis of this elusive clinical entity may be costly, potentially resulting in delay of intervention and adverse effects of alternate therapies such as anticoagulation.