1 INTRODUCTION
Left atrial (LA) thrombus is associated with atrial fibrillation (AF)
and mitral valve disease in most cases. Although other conditions such
as low cardiac function and coagulation abnormalities can cause LA
thrombi, LA thrombus without atrial fibrillation or mitral valve disease
is very rare. Most LA thrombi form within the left atrial appendage, but
when thrombi form in the left atrium, distinguishing the thrombi from
the LA tumors is often difficult. We report a case of a man with no
history of AF or mitral valve disease who underwent LA mass resection
for suspected LA tumor, which turned out to be a large thrombus after
the surgery.