Papillary fibroelastoma causing severe aortic stenosis

Abstract

Herein, we present a rare case of papillary fibroelastoma of the aortic valve, which caused severe aortic stenosis. The papillary fibroelastoma developed on the left ventricular side of the non-coronary cusp, immobilizing the cusp motion and obstructing the left ventricular outflow tract, resulting in severe aortic stenosis that brought on acute heart failure. The patient underwent an urgent surgical treatment, which resulted in a successful outcome. To the best of our knowledge, this is the first case of papillary fibroelastoma in which aortic stenosis was so severe as to cause congestive heart failure.

Learning objective

Papillary fibroelastoma (PFE) is the most commonly observed primary cardiac tumor in adults that commonly involves left heart chambers. While PFEs often cause embolisms, they rarely cause valvular dysfunction. In a case presented herein, a PFE developed on the left ventricular side of the non-coronary cusp, immobilizing the cusp motion and obstructing the left ventricular outflow tract, resulting in severe aortic stenosis that brought on acute heart failure.

Introduction

Papillary fibroelastoma (PFE) is a benign primary cardiac tumor that commonly involves left heart chambers. Since cardiac imaging modalities, such as transthoracic (TTE) and transesophageal echocardiography (TEE), multi-slice computed tomography (CT), and cardiac magnetic resonance imaging have come into wider use, PFE has become the most commonly observed primary cardiac tumor in adults [1]. While PFEs often cause embolisms, they rarely cause valvular dysfunction [1]. Herein, we present a rare case of PFE that developed on the aortic valve resulting in severe aortic stenosis (AS).

Case report

A 77-year-old female patient was transferred to our hospital with the chief complaint of chest pain. Although this chest pain had already subsided upon admission, the patient was recognized as suffering from persistent wheezing and hypoxia. The patient had experienced chest pain on exertion several times for a month before the transfer, but had not felt shortness of breath or faintness. An electrocardiogram showed sinus tachycardia, complete left bundle branch block, and inverted T waves with ST depression in leads I, II, III, aVF, and V5–6. A chest roentgenogram showed pulmonary congestion and pleural effusion with a cardiothoracic ratio of 46 %. A TTE disclosed a tumor, 15 × 11 mm in size, on the left ventricular (LV) side of the non-coronary cusp (NCC) of the aortic valve (Fig. 1). The TTE also revealed severe AS with an aortic valve area of 0.38 cm², a peak transvalvular pressure gradient of 70.3 mmHg, maximal velocity of 4.2 m/s (Fig. 1), and mild aortic regurgitation (AR). The LV function was well preserved without asynergy, and an emergent coronary angiography showed 75 % stenosis in the left anterior descending artery (LAD). TEE confirmed the tumor on the LV side of the NCC, which had almost entirely obstructed the aortic valve orifice in systole (Fig. 2, Video S1). The patient's worsening congestive heart failure indicated the urgent need for surgical treatment. While in surgery, a stalkless tumor on the LV side of the NCC (Fig. 3A) was seen immobilizing the NCC and, in turn, obstructing the aortic valve orifice. Each of the aortic cusps had slightly thickened, necessitating the aortic valve replacement with a bioprosthetic valve, and a coronary artery bypass grafting to the LAD was also performed. After the surgery, the patient made a successful recovery. A pathological study showed that the tumor consisted of branching frond by central avascular elastic and collagen tissue core and the endocardial lining (Fig. 3B, C), which confirmed the diagnosis of PFE.

Fig. 1.

Transthoracic echocardiography, showing a tumor on the aortic valve (left, arrowhead) and continuous Doppler waveform image (right). LV, left ventricle; LA, left atrium; Ao, aorta.

Fig. 2.

Transesophageal echocardiography, showing a tumor on the aortic valve (arrowhead).

AML, anterior mitral leaflet; LV, left ventricle; LA, left atrium; Ao, aorta.

Fig. 3.

Intraoperative view, showing a tumor on the aortic valve (A). Pathological findings of the resected tumor from hematoxylin and eosin staining (B) and from elastica van Gieson staining (C). NCC, non-coronary cusp.

Discussion

Improvements in cardiac imaging modalities and their growing application have culminated in the increased detection of even small cardiac tumors, resulting in cardiac PFE becoming the most common benign cardiac tumor in adults [1]. We investigated a total of 1320 cases of PFE from four major reports [1], [2], [3], [4]. Among these, 1069 PFEs arose from the heart valves, while the other 251 PFEs originated from the nonvalvular endocardial surfaces. As for the valvular PFEs, they were most seen developing on the aortic valve (622 cases, 58.2 %), followed by the mitral valve (298 cases, 27.9 %), the tricuspid valve (93 cases, 8.7 %), and the pulmonary valve (56 cases, 5.2 %).

While the various cardiac imaging modalities have detected a variety of asymptomatic PFEs, embolisms are the most presented in patients with PFE. It seems like that PFEs themselves or that fragmented PFEs are a cause of embolisms, and that thrombi forming on the surface of PFEs can be an embolic source [2]. Gowda et al. [2] reported that the tumor mobility was the risk factor for both PFE-related death and nonfatal embolization. In a separate study, both stalk and tumor mobility were found to be predictors of embolic risk [3]. In contrast to these embolic complications, PFEs themselves rarely were seen as the cause of valvular dysfunctions. Gowda et al. [2] stated that PFEs cause mitral or tricuspid stenosis by obstructing the valvular orifice and aortic, mitral, and tricuspid regurgitation. However, regarding the AS, they only mentioned the possibility that PFEs cause AS. A further study by Ikegami et al. [5] analyzed 21 PFE cases originating from the aortic valve, reporting no AS or AR cases caused by PFEs, while a study by Buppajarntham et al. [6] reported only a single case of AR caused by the traction of the NCC by PFE. A single case of AS associated with PFE and complicated with new pulmonary embolisms and the constrictive pericarditis was reported by Anastacio et al. [7] with that case presenting with recurrent respiratory symptoms and new bilateral lower extremity swelling 3 months after the resection of PFEs on the pulmonary valve and the right atrium. Although few details describing the AS were given, the PFE on the aortic valve was reported as being 10 × 7 mm. Also, while the symptoms appear related to pulmonary embolisms and the constrictive pericarditis, the severity of the AS did not seem equal to the case presented herein. In our case, the stalkless PFE, which had developed on the LV side of NCC and measured 15 × 11 mm, not only immobilized the cusp but also obstructed the aortic valve orifice, and these two mechanisms contributed to the occurrence of severe AS. The actual cause of the development of acute heart failure can only be speculated, but it is likely to be rapid tumor growth or rapid progressive protrusion of the tumor into the aortic valve orifice. In accordance with our findings, we concluded this case to be an extremely rare case of PFE on the aortic valve causing heart failure with pulmonary congestion. The rare nature of PFEs on the aortic valve that causes AS may reflect the fact that these types of PFEs tend to cause embolic complications long before growing large enough to result in AS.

In cases with a mass found on the aortic valve, it is essential to differentiate vegetation seen in infective endocarditis (IE), native aortic valve thrombus, calcified amorphous tumor (CAT), Lambl's excrescences, and tumor. In the present case, there was no sign of a systemic infection, such as high-grade fever, and increased white blood cell count and C-reactive protein level, so IE was ruled out. Native aortic valve thrombi develop on the aortic side of the cusps especially at the base of the cusp [8]. CAT can develop in all cardiac chambers, but predominantly develop on the mitral valve or annulus, and rarely on the aortic valve [9]. CAT consists of nodular calcium deposits, so it appears as a high-echoic mass on echocardiography. Lambl's excrescences appears as filiform fronds located at the valve closure line, so it resembles a tumor on the aortic valve, and will be difficult to distinguish from a tumor when it becomes giant [10]. Aortic valve tumors other than PFE are rare, and include myxoma, fibroma, lipoma, fibrolipoma, and hemangioma. TTE, TEE, and CT have enabled the detection of aortic valve tumor more easily, however, pathological study remains the gold standard of differential diagnosis of these tumors.

Since the clinical presentation of cardiac PFE varies from the asymptomatic to sudden death, a therapeutic strategy has remained controversial as both the presence of symptoms and the potential for life-threatening complications need to be considered. In general, a consensus for surgical treatment has been reached in treating symptomatic patients; however, an appropriate strategy for asymptomatic patients with incidentally detected PFE is still a matter of debate [5]. Currently, however, Ngaage et al. [4] recommend prompt surgical resection in all cases of cardiac PFE to avert the potential for serious neurologic complications, and Tamin et al. [1] recommend surgery in the case of good surgical candidates (Society of Thoracic Surgeons score < 1 %) with left-sided PFE, regardless of their size, mobility, or location. On the other hand, several authors have called for limits on surgical treatment in asymptomatic patients when PFEs are mobile and/or larger than 1 cm, and could otherwise be observed in close follow-ups [2].

Regarding surgical treatment, shaving of the tumor may be possible in most patients without any recurrence of the tumor. In the case presented herein, the aortic valve cusps were slightly thickened, and a mild AR addition to the severe AS was recognized, so the aortic valve was replaced. Although there is a lack of clear evidence for anticoagulant or antiplatelet drugs' efficacy, for patients not considered surgical candidates or for those who refuse surgery, one is generally recommended to prevent thrombus formation on the tumor [1].

The following is the supplementary data related to this article.

Video 1

Transesophageal echocardiography shows a tumor on the left ventricular side of the non-coronary cusp obstructing the aortic valve orifice in systole.

Declaration of competing interest

The authors declare that there is no conflict of interest.