We present what we believe is the first case in the literature of carc
inoma of the lung presenting de novo as an intracardiac mass with bila
teral, simultaneous popliteal artery embolization. Arterial thromboemb
olism of cardiac origin and in situ thrombosis of a preexisting athero
sclerotic lesion or aneurysm account for the majority of cases of acut
e lower extremity ischemia. Less common causes include trauma, aortic
dissection, venous ischemia, and foreign body or tissue embolization.
Although the history, physical examination, and electrocardiographic f
indings may provide a likely explanation in many cases, noninvasive st
udies such as echocardiography may help further elucidate the embolic
source.