Antiphospholipid syndrome is characterized by recurrent spontaneous abortion, recurrent arterial/venous thrombosis, and thrombocytopenia. The presentation of an atrial mass mimicking a myxoma in this syndrome is exceedingly rare, leading to misdiagnosing of the condition and further risking recurrence due to lack of anticoagulation. In this report, we present such a case that was mistakenly thought to be a myxoma.