Atrial Thrombus or Atrial Myxoma? Preliminary Analysis of Echocardiographic Findings of a Case Series.

Background: Echocardiography has been proven to be a useful tool for detecting atrial-occupying lesions, ranging from primary or secondary tumors to thrombi. Although the precise diagnosis is important as clinical treatment modalities differ, sometimes differentiating a thrombus from a myxoma is very difficult.

Case report: From January 2019 to December 2022, we retrospectively analyzed the echocardiographic findings of 8 patients who were found to have an interatrial mass. Of the 8 patients, 4 had a right atrial mass, and 4 had a left atrial mass. Based on ultrasonic examination, the initial diagnosis was a thrombus and the second diagnosis was a myxoma for all 8 patients. All masses were finally confirmed to be thrombi. Although an echocardiogram can provide significant information on the nature of atrial masses in many patients, qualitative diagnosis of a small percentage of atrial masses remains difficult.

Conclusion: An atrial thrombus is occasionally difficult to differentiate from an atrial myxoma in patients without atrial fibrillation, especially when it is not attached to the left atrial appendage. Upon review of the echocardiographic findings of the 8 patients described in our study, it is essential to highlight the fact that a thrombus can mimic a myxoma and thereby create a diagnostic conundrum.