The PFE is the third most common primary tumor of the heart and most frequently involves the cardiac valves [
2]. PFEs have well-established echocardiographic characteristics. The sensitivity and specificity of TTE were 88.9% and 87.8%, respectively, with an overall accuracy of 88.4% for the detection of PFE ≥ 0.2 cm [
3]. These include a round, oval and irregularly shaped tumor, usually smaller than 1.5 cm, a stalk attachment to the endocardium, they are mobile if attached by such a stalk, and often have a refractive appearance with areas of echo-lucency [
3,
4]. PFEs are an avascular connective tissue core surrounded by a looser matrix, with multiple adjacent fronds covered by endothelium [
3]. These masses must be differentiated from other cardiac mass-like lesions such as myxomas, vegetation, fibromas, Libman-Sacks vegetations, Lamble's excrescences, or thrombi. Myxomas are usually located in the left atrium and originate from the mid portion of the atrium [
5]. Infective vegetations are usually associated with clinical signs of endocarditis and valvular destruction, and may resolve or change in appearance over time with treatment [
6]. In our patient, the blood tests obtained to rule out endocarditis were negative and specific-endocarditis symptoms were not noted. Fibromas usually occur in children and young adults and typically involve the left ventricle, right ventricle and septum [
7]. Lamble's excrescences are considerably smaller and broader-based than PFEs [
8]. Thrombi are typically located in the atrial appendage, associated with atrial fibrillation and mitral valve disease or occur in regions with ventricular aneurysm and akinesia, both of which are usually secondary to myocardial infarction or cardiomyopathy and the echocardiographic finding has an irregular or lobulated border and absence of a pedicle [
9]. In this patient, It was unlikely to be a thrombus because of the location and features of the mass and the presence of a stalk. Although the patient received anticoagulation treatment with heparin, the mass size remained unchanged. The Libman-Sacks vegetations are generally rounded and sessile, less than 1 cm
2 in size, almost exclusively seen on the mitral and aortic valves and rarely on the right heart valves; they have irregular borders, heterogeneous echodensities and no independent motion. Most valves with masses have associated thickening or regurgitation [
10].
Most PFEs are asymptomatic; rarely, they are diagnosed because of cardiac symptoms or an embolic event [
11]. There are no guidelines for the management of PFEs. No data exist to evaluate the efficacy of anticoagulation or antiplatelet therapy for patients with PFE, although it is speculated that deposition of thrombotic material on the tumors may add to the risk of microembolization [
3]. However, as long as there are no definite contraindications to surgery, the only independent predictor of mortality or non-fatal embolization is tumor mobility; surgical excision is strongly recommended for patients with a highly mobile PFE with a stalk [
9]. Surgical intervention was the first line treatment recommended for this patient. However, there were no clinical manifestations from the mass such as embolization, followed by heart failure, and the patient refused surgery. And it was relatively the small size mass in the right sided heart. Therefore, the patient was followed closely for three years. There is another case reported with a mobile PFE conservatively managed for more than four years in the literature [
1].