Despite the development of imagistic methods, the differential diagnosis of a right atrial mass may be difficult to be established, the most common pathologies which should be taken in consideration being represented by thrombus, tumors, prominent crista terminalis, or vegetation of infectious endocarditis. In this study, we present the case of a 63-year-old man with chronic kidney disease, in hemodialysis (HD) with a silicone central venous catheter (CVC) with the incidental transthoracic echocardiography (transthoracic echocardiogram, TTE) finding of a tumoral mass of 35x26 mm in the right atrium (RA), not related with the catheter, which was diagnosed as right atrial myxoma and underwent surgical excision. After reviewing the histopathology probe, the diagnosis of right atrial thrombus was confirmed. In conclusion, differentiating intracardiac right atrial masses (RAMs) could may prove challenging. In our patient, clinical presentation and the preoperative investigations could not differentiate the right atrial thrombus from a myxoma, and only the postoperative histopathology diagnosis was able to guide correct diagnosis.