Due to the proximity of the transvers sinus (TS) to the left atrial
appendage (LAA) and pulmonary veins (PV), a mass in the TS can be
misinterpreted as a LAA or PV thrombus, and considered as a source of
emboli in a patient with stroke or TIA . The incorrect identification of
a mass as a LAA thrombus would initiate unnecessary anticoagulation
therapy or potentially, an evaluation for the excision of the mass if
there is a concern about dislodgement . We are presenting a case
illustrating this confusion and review the literature for similar cases.