Surgical removal from unusual location of dual papillary fibroelastomas arising from the sinotubular junction of the ascending aorta: a case report

Introduction

Primary cardiac tumours are infrequent, the majority of cases involve benign entities. Among these, cardiac myxomas, lipomas, and papillary fibroelastomas are the most prevalent types (1). Fibroelastomas represent a rare cardiac pathology, with an incidence of less than 0.1% (2). Numerous pathophysiological mechanisms have been posited concerning the genesis of fibroelastomas; however, a definitive mechanism remains elusive. Among the prevailing hypotheses, one prominent theory suggests that fibroelastomas originate from microthrombi that adhere to valvular surfaces in the presence of endothelial damage. Over time, these microthrombi undergo progressive transformation, culminating in the development of fibroelastomas (2).

Fibroelastomas typically arise from the endocardium of cardiac valves (1). The aortic valve is the most common site for the development of papillary fibroelastomas, followed by the mitral valve, cardiac chambers, tricuspid valve, and pulmonary valve, in descending order of frequency (3). The occurrence of a fibroelastoma originating directly within the aorta, devoid of any valvular association, is exceedingly rare and has only been reported by a few authors in medical literature (4-8).

This case report describes a scenario where a patient was incidentally found to have a mass arising from the sinotubular junction of the ascending aorta that after excision turned out to be dual papillary fibroelastomas. We present this article in accordance with the CARE reporting checklist (available at https://amj.amegroups.com/article/view/10.21037/amj-24-97/rc).

Case presentation

A 75-year-old woman presented to rapid access chest pain clinic in her local district general hospital, in November 2023, with paroxysmal, dull, non-exertional chest pain radiating to the left axilla. On performing an electrocardiogram the patient was diagnosed with atrial fibrillation, with a heart rate of 118 beats/min, which was managed with edoxaban 60 mg once daily and bisoprolol 1.25 mg once daily. She had past medical history of asthma, hypercholesterolaemia, and hypertension. She was on atorvastatin 40 mg once daily and ramipril 2.5 mg once daily. She intermittently used two puffs of salbutamol inhaler. A transthoracic echocardiogram (TTE) performed, in December 2023, as work-up for evaluation of atrial fibrillation revealed a small mobile echogenic mass in the aortic root measuring 0.6–0.8 cm. Upon further investigation with a computed tomography (CT) scan, a 10.6 mm × 9.8 mm mass lesion arising posteriorly from the ascending aorta was reported (Figure 1A). The mass was in close proximity to the origin of the left main stem coronary artery but the origin of the right coronary artery was well clear. CT coronary angiogram reported normal coronary arteries. The patient was referred for excision of the mass to the tertiary cardiac surgery hospital in January 2024. The case was discussed in the aortovascular multidisciplinary team meeting, a differential diagnosis of thrombus or tumour proposed, and the recommendation was to excise the mass due to potential risk of stroke.

Figure 1 Diagnostic imaging. (A) Computed tomography scan showing location of the mass (white arrow). (B) Transoesophageal echocardiogram showing the mass attached to the sinotubular junction of the ascending aorta (white arrow) and its relationship to the aortic valve.

A week later, scheduled elective surgery was performed to excise the mass lesion in the ascending aorta. Following the administration of general anaesthesia, the patient was positioned supine, prepared, and draped. Intraoperative transoesophageal echocardiogram (TOE) revealed the presence of a pedunculated mobile mass (Figure 1B). A median sternotomy was performed, subsequently followed by a vertical pericardiotomy. A full dose of heparin was administered, and cardiopulmonary bypass (CPB) was initiated using a single two-stage venous cannula inserted into the right atrium for venous return, and a standard arterial cannula into the ascending aorta for systemic perfusion of oxygenated blood. Prior to initiating cardioplegia, the aorta and pulmonary artery were meticulously dissected to expose the anterior aspect of the aortic root up to the left coronary artery.

The systemic temperature was maintained at normothermia throughout the procedure. Following the cross-clamping of the aorta, antegrade cardioplegia was administered into the aortic root. An initial dose of 1.2 litres of cold blood cardioplegia was delivered, successfully providing myocardial protection and achieving prompt diastolic arrest. The procedure was accomplished in its entirety with a single dose of cardioplegia.

A transverse incision, approximately 1.5 cm above the sinotubular junction, was made to access the mass. The mass was located in close proximity to the aortic valve and encroaching upon the left main stem. Upon extraction of the gelatinous mass, two distinct masses, resembling fibroelastoma in appearance, were identified. Both masses were excised and subsequently submitted for histopathological analysis. Given the propensity of fibroelastomas for embolization, a meticulous examination of the aorta and left ventricle was conducted to ensure the removal of any potential fragments. The aortotomy was closed with a 4/0 prolene suture. Once aortotomy was closed, the aorta was unclamped after de-airing manoeuvres. De-airing was effectively accomplished using the cardioplegia cannula. The controlled gradual reduction of CPB flow was meticulously managed to ensure the maintenance of stable hemodynamics. Patient was successfully separated from CPB. Additionally, two ventricular pacing wires were securely affixed to the right ventricle, and a pacing box was programmed with a backup rate of 60 beats per minute. It is noteworthy that the patient spontaneously recovered sinus rhythm with a rate of 70 beats per minute. After these procedural measures were completed, the sternum was closed with steel wires and the incision closed in layers. The total CPB time was 22 min and the cross-clamp 14 min. Postoperative TOE revealed preserved biventricular function, normal valvular function, and no visible mass in the ascending aorta.

The patient was transferred to the intensive care unit in a haemodynamically stability condition and the immediate postoperative course was uneventful. On postoperative day 2, the patient had a brief episode of self-terminating atrial fibrillation. The remainder of her hospital stay was unremarkable and she was discharged home on postoperative day 5 with satisfactory recovery reported on 6-week follow-up visit.

The histopathology report stated receiving two pieces of gelatinous tissue. The first piece measured 15 mm × 10 mm × 5 mm and the second piece measured 12 mm × 5 mm × 3 mm (Figure 2). Sections of the two specimens, revealed fragments of branching fronds of paucicellular, avascular fibroelastic tissue lined by a single layer of endocardium, in keeping with a fibroelastoma. All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Figure 2 Double papillary fibroelastomas excised from the sinotubular junction.

Discussion

While numerous case reports have documented the excision of fibroelastomas, the present case exhibits a distinctive feature: the mass arising from sinotubular junction, an atypical location, comprised of two distinct fibroelastomas, as clearly depicted in postoperative image (Figure 2). Unlike the majority of reported fibroelastoma, which typically manifest as single mass, this instance showcased a unique presentation of dual entities. Both masses exhibited the characteristic outer appearance of a fibroelastoma, characterized by a pedunculated central stalk with projecting speckled arms (1).

Papillary fibroelastomas are commonly detected attached to a cardiac valve with 84% reported to be valvular in origin, responsible for 75% of valvular cardiac tumours (1,9). The aortic valve is involved most commonly, although all valves have been affected (9,10). The involvement of extravalvular sites is particularly rare.

There have been sparse reports of origin of papillary fibroelastomas from unusual sites. The left ventricle has been the predominant extravalvular site of tumour location (2,11-13). However, many other sites have been reported including: the left atrium (2,11), left atrial appendage (14,15), coumadin ridge (16), atrial septum (11,17), right atrium (11,18), right atrial appendage (19), Eustachian valve and Chiari network (20,21), right ventricle (2,11), chordae (22), and papillary muscle (23). The ascending aorta is another extravalvular site with only a handful of cases (4-8) reporting origin of fibroelastomas from this atypical location (Table 1).

TOE maintains its status as the preferred diagnostic modality for detecting papillary fibroelastomas over TTE. Approximately one in four patients with fibroelastomas evade detection during initial evaluation by TTE but are subsequently identified through TOE examination (4). Echocardiography facilitates comprehensive visualisation of the tumour, enabling precise measurement of its dimensions, assessment of pedunculated mass mobility, and determination of attachment sites. In this case CT scanning was also performed as comprehensive imaging is crucial for devising effective treatment strategies for patients with fibroelastomas.

Despite their benign histology, fibroelastomas can precipitate numerous life-threatening complications. Their inherent mobility predisposes them to embolize to systemic arterial beds, resulting in potentially fatal events such as myocardial infarctions, strokes, transient ischemic attacks, and peripheral embolization (6). Additionally, when fibroelastomas are attached to cardiac valves, they can impede valvular function, leading to regurgitation or stenosis. Moreover, fibroelastomas have the capacity to disrupt normal electrical conduction pathways within the heart, thereby precipitating arrhythmias such as atrial fibrillation, ventricular tachycardia, or complete heart block. Rarely, they can precipitate acute myocardial infarction from either mechanical occlusion of coronary ostium or embolization (5).

Fibroelastomas can be managed via surgery or close monitoring. Surgical excision remains the primary treatment approach for symptomatic fibroelastomas or those deemed to carry a heightened risk of embolization (3). A full CPB is required when undertaking a surgical excision of the fibroelastoma. The pedunculated mass is attached to a pedicle, precise excision at this point ensures complete removal of the cardiac tumour and any residual tissue.

This case illustrates an exceptionally rare finding of papillary fibroelastoma originating from the ascending aorta. This is only the sixth reported case of fibroelastoma at this location (Table 1). Three of the five cases reported cardiac symptoms of angina and dyspnea secondary to either the tumor embolizing down the coronary artery or occluding the coronary ostium. The remaining two cases described neurologic deficits as a result of fragments breaking off from the tumor and embolizing to the brain. Contrary to the previously reported cases, this patient had no symptoms secondary to the pathology and the tumor was detected incidentally. Three tumors were first identified on TOE, one was detected on ventriculography during conventional coronary angiography, and one was recognized on TTE similar to this case. All previously reported cases had a single tumor unlike this case which had two tumors. The sizes of both the fibroelastomas of this case resembled those reported previously. Surgical excision was performed for all except one previously reported cases similar to this case. All patients in the published case reports were discharged following surgery within 7 to 10 days with the patient in this case report having a shorter length of stay of 5 days possibly due to shorter CPB and cross-clamp times. No recurrence was reported by any of the published cases similar to our experience.

This case report is exceptional for several reasons namely the unusual location and duality of the tumour, the lack of symptoms and incidental detection of the pathology, the timely treatment, quick postoperative recovery, and good short-term outcome. The lack of information about long-term prognosis including late recurrence is a limitation of this case report.

Conclusions

Dual papillary fibroelastomas of the sinotubular junction is an extremely rare occurrence that should be excised to avoid embolic sequelae and verify the diagnosis.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://amj.amegroups.com/article/view/10.21037/amj-24-97/rc

Peer Review File: Available at https://amj.amegroups.com/article/view/10.21037/amj-24-97/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://amj.amegroups.com/article/view/10.21037/amj-24-97/coif). S.G.R. serves as an unpaid editorial board member of AME Medical Journal from April 2024 to June 2026. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional research committee and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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