Formation of a left atrial ball thrombus from a large mural thrombus 4 days after an embolic episode

We present a case of basilar artery embolism originating from a left atrial mural thrombus. The thrombus was large and attached to the posterior left atrial wall, but decreased in size and detached forming a ball type thrombus over the next 4 days without anticoagulant and/or antifibrinolytic therapy.