Abstract
BACKGROUND: Right atrial thrombosis is a rare but serious condition that can mimic cardiac tumors like myxoma, posing diagnostic challenges. It often presents with nonspecific symptoms, making early detection difficult and critical for preventing complications such as embolism or heart failure. CASE SUMMARY: We report a case of a large right atrial mass initially suspected as myxoma. Laboratory tests showed elevated D-dimer (1,000 ng/mL, normal: <800 ng/mL) with normal coagulation profile and negative antiphospholipid antibodies. Imaging and clinical evaluation led to the diagnosis of a huge right atrium thrombosis rather than myxoma. DISCUSSION: Distinguishing thrombus from myxoma is crucial due to differing management strategies. Elevated D-dimer and negative autoimmune markers supported thrombosis. Echocardiography played a pivotal role in diagnosis. Awareness of such presentations can prevent unnecessary surgery. TAKE-HOME MESSAGES: Right atrial thrombosis can mimic myxoma clinically and on imaging. Comprehensive evaluation including coagulation studies, autoimmune markers, and echocardiography aids accurate diagnosis, guiding appropriate treatment and improving outcomes.