Lambl’s excrescences (LEs) are delicate, mobile, endothelial-covered filaments arising along the coaptation lines of cardiac valves, most often the aortic and mitral valves [1]. Although they were described by Vilém Dušan Lambl as early as the 19^th century, their clinical significance is still a subject of ongoing research [2]. These structures were initially described as incidental findings in echocardiographic studies and are often thought to arise from degenerative changes or mechanical stress on the valve endocardial surfaces, usually at the coaptation margins [3]. Initially thought to be an incidental finding with no clinical significance, LEs have been increasingly recognized in the context of embolic stroke, particularly in patients without other obvious sources of emboli [2][4]. Their detection has become more frequent with advances in imaging techniques, particularly trans-esophageal echocardiography (TEE), which allows for detailed visualization of these structures.

A 64-year-old Caucasian woman with a history significant for hyperlipidemia, hypothyroidism, celiac disease, and smoking presented to the emergency room with a witnessed episode of transient right upper arm paresis and monocular transient loss of vision in the right eye, lasting for approximately 3 minutes. There were no associated dysarthria, vertigo, or auditory symptoms. Her vital signs were within normal limits, and a physical examination in the emergency room was without any abnormality.

LEs are small, filiform projections found on heart valves, typically discovered incidentally during echocardiographic or autopsy studies. They are most commonly seen to arise on the aortic or mitral valve but may be seen on right-sided valves as well [5]. Histologically, they are composed of a core of connective tissue (collagen and elastin), covered by a layer of endothelial cells [6]. Pathophysiologically, their origin is not well defined but believed to be initiated by endothelial damage to the heart valves from the shear stress due to blood flow, with resultant endothelial tear, followed by fibrin deposition, microthrombi, and endothelial growth [7]. They tend to develop in the Nodulus Arantius and the free margin of the aortic cusp [6]. Embolization of the small fragments or microthrombi can cause TIA or stroke. Another hypothesis is that it can act as a nidus for platelet aggregation and clot formation. Often seen as benign, they have been linked to embolic events by association, although there is a lack of strong evidence to show causality. Retrospective studies showed a higher prevalence of LEs in stroke/TIA patients compared with controls, but prospective data are less supportive [1][8]. However, in contrast, there are case reports and case series showing an association between LEs and stroke [2][4][9].

Differentiation from papillary fibroelastomas (PFEs) and infective vegetations is critical, as management differs. PFEs tend to be bulkier and frond-like morphologically, in contrast to the thin and filamentous structure of LEs, and arise away from the valve leaflet coaptation lines, although there can rarely be giant LEs (>2 cm), making this differentiation difficult solely on TEE. Infective vegetations are irregular non-filamentous masses with variable echogenicity and are usually accompanied by valvular dysfunction, which is in contrast to LE, which does not affect valve function. Echocardiography is the initial test of choice for interrogating cardiac valves due to its low cost, wide availability, and temporal and spatial discrimination. TEE offers superior spatial resolution for detecting these slender lesions, which are often missed on transthoracic studies [10].

There are no consensus guidelines for the management of LEs. The three available options in their management include observation, antiplatelet medications (single or combined antiplatelet therapy)/anticoagulation, and surgical resection [11][12]. The choice of therapy is dictated by the presence of symptoms, surgical risk, and ongoing treatment. Asymptomatic patients are usually observed. For symptomatic patients without an alternative embolic source, initial single antiplatelet therapy is reasonable. Escalation to dual antiplatelet therapy, anticoagulation, or surgical excision may be considered for recurrent events [13]-[15]. In our patient, single antiplatelet therapy was chosen given the transient, isolated episode, absence of arrhythmia, and lack of recurrent symptoms. In contrast, if the patient had recurrent episodes or a large mobile valvular lesion, we would have considered anticoagulation or surgical intervention.

After conducting a thorough workup and ruling out other possible causes of TIA, including carotid artery disease, atrial fibrillation on monitoring, intracardiac shunt, and significant aortic atheroma, Lambl’s excrescence was considered to be the most probable etiology. A definite relationship between TIA and LEs has not been established, and the association is mainly clinical.

Lambl’s excrescences, while often incidental, may be implicated in embolic events, particularly when other sources are excluded. In our patient, an extensive diagnostic workup did not identify an alternative embolic source; therefore, Lambl’s was considered the most likely etiology by exclusion. Management should be individualized, balancing recurrence risk against the risks of anticoagulation or surgery. Further prospective studies are needed to clarify their clinical significance and inform guidelines.

Each author contributed equally and substantially in the conception, write-up, revision, and final proofreading of this manuscript.

This is a case report with no identifiable patient information. Written informed consent was obtained from the patient.