Many cases of cardiac masses have been reported in the literature, but in this case report we described a rare case of biatrial cardiac mass that represented a challenge for diagnosis and therapy. In our patient, the characteristic of a left atrial mass adhering to the atrial septum posed a diagnostic challenge in differentiating between thrombus and myxoma, the most commonly reported cardiac masses. The following discussion will review cases of biatrial masses in patients with MS reported between 2008 and 2016 (Table
1). First, a 40-year-old woman with rheumatic MS was found to have biatrial thrombi mimicking myxoma, and she underwent a successful thrombectomy and valve replacement [
8]. Second, a 77-year-old man with AF, severe MS and heart failure presented with dyspnea. TEE and TTE revealed biatrial thrombi confirmed by pathological examination following thrombectomy and mitral valve replacement [
9]. Third, a 58-year-old woman presented with acute limb ischemia; she was found to have mobile biatrial thrombi, AF, and MS and underwent successful embolectomy, thrombectomy, and mitral valve replacement [
10]. The features of biatrial thrombi, MS, and AF were common to all three patients. In addition, a case of biatrial myxoma with mild MS presented with cerebral ischemia was successfully treated with thrombolytic therapy administered intravenously and surgical resection [
11]. However, numerous cases of cardiac mass with or without mitral valve disease with diagnostic difficulties have been reported earlier. Overall, cardiac thrombi were frequently reported [
5,
7,
10,
12,
13]. In some instances a cardiac thrombi mimicked atrial myxoma [
5,
7]. By contrast, atrial myxoma can simulate thrombus in the setting of MS [
14]. Of interest, a thrombus could form on top of a myxoma. In one case report of a patient with MS, the left atrial mass showed features of thrombus characterized by echocardiography and CMR. However, histopathological evaluation of the left atrial mass removed during surgery revealed a massive thrombus formed on top of a very small pre-existing left atrial myxoma [
12]. To complicate matters further, atrial thrombus may have a stalk [
6] or neovascularization [
13] mimicking atrial myxoma, potentially leading to a delay in anticoagulation therapy. In another case report, biatrial intracardiac masses were detected by three-dimensional TEE in an 80-year-old woman with heart failure, mitral valve repair, dual chamber permanent pacemaker implantation, and AF. Although direct pathological specimens were not obtained, the reduction in the size of both masses after intensive anticoagulation treatment raises the strong possibility that both masses were thrombi [
15]. This case report highlighted the facts that anticoagulation is a feasible treatment in regressing thrombi when surgery is relatively contraindicated in an older patient with comorbidities.
Table 1
Biatrial mass with mitral stenosis
| 2008 | 51/male | Right hemiparesis | – | Myxoma | Alteplase administered intravenously + tumor excision |
| 2008 | 58/female | Left foot pain | + | Thrombi | Thrombectomy + MV surgery |
| 2010 | 77/male | Dyspnea | + | Thrombi | Thrombectomy + MV surgery |
| 2015 | 40/female | Dyspnea | + | Thrombi | Thrombectomy + MV surgery |
TEE is superior to TTE in delineating and characterizing cardiac masses [
2]. CMR provides high spatial resolution images, improves tissue characterization and is complementary to echocardiography in the assessment of cardiac masses [
3]. Common CMR sequences are cine image, T1-weighted and T2-weighted spin echo, contrast first pass perfusion, and standard delay enhancement. However, tumors and chronic organized thrombi cannot be distinguished from one another using the morphology, motility, and enhancement patterns by CMR. A pattern of hyperintensity/isointensity (compared with normal myocardium) with short T1, and hypointensity with long T1, was very frequent in thrombi, rare in tumors, and had the highest accuracy for the differentiation of both entities [
4]. In addition to conventional imaging studies, the assessment of vascularity either by myocardial perfusion contrast echocardiography [
16] or cardiac catheterization may assist in the differentiation of thrombi and other type of cardiac tumors. Nevertheless, in a few instances, the final diagnosis of cardiac masses can only be made by obtaining a pathological specimen after surgical resection of cardiac masses [
5‐
7,
12].
For our patient, the nature of biatrial mass was not specified by histology because he declined surgery. The presence of MS, AF, SEC and dilated LA indicated a diagnosis of thrombi. Our case is unusual because the final diagnosis was affirmed by empirical anticoagulation based on clinical judgment and noninvasive characterization of biatrial mass. A reported case of left atrial thrombus with a stalk showed that a trial of anticoagulation was beneficial in regressing the cardiac mass particularly when the differential diagnosis was difficult and thrombus was a possibility [
6]. There were also cases that reported successful regressions of the thrombus with anticoagulation without the need for surgical thrombectomy [
15,
17,
18]. Regression of thrombus using warfarin has been studied in patients with MS and left atrial thrombus detected prior to percutaneous transvenous mitral commissurotomy. Among 219 patients following 6 months of warfarin (INR 2 to 3) therapy, 24.2 % of patients were found to have complete resolution of thrombus and 75.8 % of patients were found to have partial resolution of thrombus, and a higher INR (at least 2.5) predicted thrombus resolution [
19]. For our patient, the regression of his cardiac masses was not observed in the short term after treatment with warfarin, casting doubt on the true identity of the biatrial mass. We suspect the main contributing factor towards the lack of thrombi regression was inadequate anticoagulation owing to his lack of compliance. For this reason, compliance to anticoagulation therapy was pivotal in thrombi regression, and it took 5 years to visualize the resolution of biatrial thrombi. Although a thorough attempt had been made, we could not convince our patient to agree to surgery. We believe that early mitral valve surgery and thrombectomy is beneficial in preventing thromboembolism.