Right atrial thrombus masquerading as myxoma

Abstract

Introduction: In-situ right atrial (RA) thrombus is a rare occurrence typically associated with heightened inflammatory or hypercoagulable states. Here, we present a case of in-situ RA thrombus mimicking atrial myxoma in a patient with sepsis and bacteraemia. Case description: A 41-year-old man presented with septic arthritis and bacteraemia caused by methicillin-resistant Staphylococcus aureus (MRSA). A transoesophageal echocardiogram revealed a large pediculated mass resembling atrial myxoma, which was not visible on transthoracic echocardiography performed four days earlier. Cardiac magnetic resonance (CMR) imaging strongly suggested a thrombus, leading to the patient undergoing transcatheter aspiration. Subsequent pathology confirmed an organised fibrin thrombus without evidence of infection. Discussion: The patient’s in-situ RA thrombus likely developed in response to a heightened inflammatory state associated with sepsis. Limited data exist on in-situ RA thrombi in the absence of atrial fibrillation, though some reports suggest a correlation between heightened inflammation and a hypercoagulable state. Conclusion: CMR imaging is invaluable for characterising such masses and can aid in distinguishing a thrombus from a myxoma.

Keywords

• right atrial thrombus
• cardiac mass
• transcutaneous aspiration