Left Atrial Fungal Mass Masquerading as Myxoma: The Importance of Histopathological Confirmation: A Case Report

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Fungal infective endocarditis is a rare form of endocarditis that occur in immunodeficient patients. Atrial myxoma are a common cause of cardiac tumors in the left atrium. However, infective endocarditis is a differential diagnosis of cardiac masses in general and atrial myxoma particularly. Case summary A 49-year-old male with subacute infective endocarditis presentation underwent an echocardiogram examination that showed a left atrial mass with features of atrial myxoma. However, the histological examination after surgical removal of the mass showed a fungal mass. Conclusion This case shows that a fungal infective endocarditis may present with a cardiac mass sharing typical features with left atrial myxoma. It also shows the importance of histological examination for the final diagnosis and a prompt treatment. Infective endocarditis Fungal cardiac mass Fungal infective endocarditis Left atrial myxoma Figures Figure 1 Figure 2 Introduction Infective endocarditis (IE) remains a life-threatening disease despite advances in diagnostic and therapeutic strategies. According to the latest European Society of Cardiology (ESC) guidelines, echocardiography plays a pivotal role in the diagnosis of IE, with the detection of vegetations, abscesses, and new valvular regurgitations being major criteria for diagnosis [1]. Blood cultures and histopathological examination further confirm the diagnosis. Although bacterial pathogens remain the most common etiologic agents, fungal IE accounts for less than 10% of cases and is associated with a particularly poor prognosis [1,2]. Fungal endocarditis predominantly affects immunocompromised patients, those with prosthetic valves, or individuals with a history of intravenous drug use [2,3]. The clinical and imaging presentation of fungal cardiac masses can mimic benign primary tumors such as atrial myxomas, complicating the diagnostic process [4,5]. We report a rare case of left atrial fungal infective endocarditis in an immunocompetent patient, initially misdiagnosed as a myxoma, highlighting the importance of considering infectious etiologies in the differential diagnosis of intracardiac masses. Case Presentation We report the case of a 49-year-old male without medical history. He had a dental extraction performed 10 months prior. The patient presented with a two-month history of prolonged fever, headaches, night sweats, anorexia, weight loss, and fatigue. He also reported joint pain, mainly in the knees, and more recently palpitations and worsening dyspnea (NYHA class III). Physical examination revealed a febrile state without cutaneous lesions. Cardiac auscultation detected a mitral regurgitation murmur. No signs of heart failure or embolic cutaneous manifestations were noted. The electrocardiogram showed a sinus rhythm at 85 beat per minute, a normal PR segment at 140 millisecond and normal QRS complexes without repolarization abnormalities. Transthoracic Echocardiography (TTE) (Figure 1) found a heterogeneous mobile left atrial mass attached to the interatrial septum and mitral valve with a diameter of 35 mm. It also showed a moderate mitral regurgitation, a left ventricular ejection fraction (LVEF) at 50% and no signs of pulmonary hypertension or pericardial effusion. Laboratory tests showed anemia (hemoglobin at 9.9 g/dL), leukocytosis (16,420/mm³), elevated CRP (111.9 mg/L, decreasing to 26 mg/L with treatment), positive blood cultures for Staphylococcus hominis and Streptococcus acidominimus . Based on the presence of positive blood cultures and the new onset of mitral regurgitation, the diagnosis of cardiac infective endocarditis was evoked and the patient received intravenous antibiotics adapted to the culture sensitivities. However, the cardiac mass was not a typical image of valvular vegetation. Because of its typical location, the diagnosis of left atrial myxoma was evoked and the patient underwent surgery. The cardiac mass was successfully removed (Figure 2) with a macroscopic aspect of a mass of 6 g and measuring 25 mm by 15 mm, calcified and grayish yellow in color. The histological examination showed primarily fibrin-like material with fibrous organization and calcium rearrangement. Filamentous mycotic elements with spore-forming elements were also present. The final diagnosis was a fungal infective endocarditis. The patient received Amphotericin B 300 mg daily for two weeks. His clinical condition improved markedly, becoming afebrile with normalization of inflammatory markers and resolution of leukocytosis. Discussion Primary cardiac tumors are rare, and myxomas represent the most common type, accounting for nearly half of them. Myxomas predominantly arise from the interatrial septum of the left atrium and typically present with obstructive cardiac symptoms, embolic events, or systemic constitutional symptoms such as fever and weight loss. Conversely, infective masses of the left atrium, particularly fungal infections, are extremely rare and often under-recognized. Fungal masses in the left atrium may clinically and radiologically mimic myxomas, posing a significant diagnostic challenge [ 6 , 7 ]. Although myxomas are relatively frequent among cardiac masses, left atrial fungal infections are exceptionally rare, particularly in immunocompetent individuals without prosthetic valves or a history of intravenous drug use [ 8 ]. Fungal endocarditis represents less than 10% of all infective endocarditis cases, with Candida albicans being the predominant pathogen [ 2 , 3 , 9 ]. When infections do involve the atria, they are more frequently bacterial and localized to the endocardium or valves. Left atrial fungal masses have only been reported sporadically in the literature [ 6 , 10 ]. The diagnostic confusion arises when a myxoma displays atypical echocardiographic features. Classic myxomas are pedunculated, mobile, and attached to the fossa ovalis region of the interatrial septum. However, atypical myxomas may appear sessile, irregular, and broad-based, sometimes lacking the typical "ball-valve" motion and resulting in a more infiltrative appearance on echocardiography [ 11 ]. These atypical characteristics overlap with those of thrombi and infective vegetations. Fungal infections of the left atrium typically appear on echocardiography as heterogeneous, poorly defined masses, sometimes associated with mural thrombus formation or adjacent tissue destruction [ 6 , 8 ]. Transesophageal echocardiography (TEE) is more sensitive than transthoracic echocardiography (TTE) for detecting vegetations and fungal masses [ 12 ]. Nevertheless, the absence of a stalk, the irregular shape, and rapid evolution of the mass may orient toward an infectious origin rather than a tumoral one [ 10 , 12 ]. On macroscopic examination, myxomas are generally gelatinous, polypoid, and well circumscribed, sometimes displaying areas of hemorrhage. In contrast, fungal masses are often friable, necrotic, and poorly circumscribed, sometimes appearing cystic or purulent [ 6 ]. Histologically, myxomas are composed of scattered polygonal or stellate cells embedded in a myxoid stroma, without any evidence of organisms. In contrast, fungal masses show thrombotic material with infiltration of yeast and hyphal forms, which can be demonstrated by Periodic Acid-Schiff (PAS) staining or Grocott methenamine silver stain [ 6 , 8 , 9 ]. Thus, histopathological analysis remains the gold standard for definitive diagnosis in such cases [ 8 , 9 ]. Despite appropriate antifungal treatment with amphotericin B, the prognosis of fungal endocarditis remains poor, often complicated by embolic events and sepsis [ 2 , 9 ]. In our case, the echocardiographic features strongly suggested the presence of a cardiac myxoma, given its relative frequency. However, the final diagnosis revealed a fungal mass, a much rarer and less well-known entity. This rarity can lead to delays in diagnosis and treatment, especially since fungal infective endocarditis requires more urgent surgical intervention than a myxoma due to its generally poorer prognosis if not managed promptly. Fortunately, surgery was performed early in our patient, resulting in a favorable outcome. The key takeaway from this case is that a fungal mass should be considered as a differential diagnosis of atrial myxoma, particularly in the presence of other signs suggestive of infective endocarditis. Conclusions This case highlights the diagnostic challenge of differentiating between infective endocarditis and primary cardiac tumors when encountering atypical intracardiac masses. Left atrial fungal endocarditis remains exceedingly rare, especially in immunocompetent patients without prosthetic valves or intravenous drug use. The echocardiographic appearance mimicking an atrial myxoma led to surgical resection, which provided the definitive diagnosis through histopathological analysis. According to ESC guidelines, the management of fungal infective endocarditis requires a combination of antifungal therapy and surgical intervention to improve outcomes. Clinicians should maintain a high index of suspicion for infectious etiologies in cases of atypical intracardiac masses to guide timely and appropriate management. Abbreviations IE Infective endocarditis ESC European Society of Cardiology NYHA New York Heart Association TTE Transthoracic Echocardiography LVEF left ventricular ejection fraction TEE Transesophageal echocardiography PAS Periodic Acid-Schiff Declarations Consent for publication Written and informed consent has been obtained from the patient to publish the case report. Funding None. Author Contribution M.N. wrote the main manuscript text and A.B. and S.H. prepared the fgures. I.B., A.A., S.H. and I.F. contributed to the research. M.C. was the supervisor. References Habib G, Lancellotti P, Antunes MJ, et al. 2015 ESC Guidelines for the management of infective endocarditis: The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC). Eur Heart J. 2015;36(44):3075–3128. doi:10.1093/eurheartj/ehv319 Ellis ME, Al-Abdely H, Sandridge A, et al. Fungal endocarditis: evidence in the world literature, 1965–1995. Clin Infect Dis. 2001;32(1):50-62. doi:10.1086/318452 Pierrotti LC, Baddour LM. Fungal endocarditis, 1995-2000. Chest. 2002;122(1):302-310. doi:10.1378/chest.122.1.302 Baddour LM, Wilson WR, Bayer AS, et al. Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications: A Scientific Statement for Healthcare Professionals From the American Heart Association. Circulation. 2015;132(15):1435-1486. doi:10.1161/CIR.0000000000000296 Bayer AS, Bolger AF, Taubert KA, et al. Diagnosis and management of infective endocarditis and its complications. Circulation. 1998;98(25):2936-2948. Revankar SG, Sutton DA. Fungal infections of the cardiovascular system. Cardiol Clin. 2003;21(4):657-674. doi:10.1016/S0733-8651(03)00046-9 Gowda RM, Khan IA, Nair CK, et al. Cardiac myxoma: a clinical and echocardiographic profile. Int J Cardiol. 2003;91(3):215-219. doi:10.1016/S0167-5273(03)00087-0 Raut MS, Maheshwari A, Dubey S, et al. A rare presentation of fungal endocarditis mimicking left atrial myxoma. Ann Card Anaesth. 2017;20(2):253-256. doi:10.4103/aca.ACA_110_16 García-Cabrera E, Fernández-Hidalgo N, Almirante B, et al. Fungal endocarditis: the ICE prospective cohort study. Clin Infect Dis. 2012;54(4):583-592. doi:10.1093/cid/cir850 Pasha AK, Lee JZ, Low SW, et al. Fungal endocarditis: Update on diagnosis and management. Am J Med. 2016;129(10):1037-1043. doi:10.1016/j.amjmed.2016.05.035 Butany J, Nair V, Naseemuddin A, et al. Cardiac tumours: diagnosis and management. Lancet Oncol. 2005;6(4):219-228. doi:10.1016/S1470-2045(05)70093-0 Evangelista A, Gonzalez-Alujas MT. Echocardiography in infective endocarditis. Heart. 2004;90(6):614-617. doi:10.1136/hrt.2003.028712 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 18 Sep, 2025 Read the published version in The Egyptian Heart Journal → Version 1 posted Editorial decision: Revision requested 24 Jul, 2025 Reviews received at journal 24 Jul, 2025 Reviewers agreed at journal 24 Jul, 2025 Reviews received at journal 23 Jul, 2025 Reviewers agreed at journal 22 Jul, 2025 Reviewers invited by journal 20 Jul, 2025 Editor assigned by journal 14 Jul, 2025 Submission checks completed at journal 14 Jul, 2025 First submitted to journal 09 Jul, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7087630","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":489380715,"identity":"924f6a01-a43f-4c78-93a3-93739c816fa2","order_by":0,"name":"MOHAMED MOUNIR NESNASSI","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8ElEQVRIiWNgGAWjYBADHghlwCAHog48IEWLMVhLAinWJTaASHxazNnbnz348adOhkHs8DHpgoJ76fPDDj8E2mInp9uAXYtlzxlzw962wzwM0mlp0jMMinM33k4zAGpJNjY7gF2LwY0cNgnehgNALTlm0jwGCbkbZyeAtBxI3IZLy/3nzyT//KmDa0k3nJ3+Ab+WGwxAlWzMcC0J8tI5BGw5A1QpC/QLm3RasjVQi+EG6ZyCAwkGePxy/PgzyTd/6uz5pZMP3ub5kyAvPzt984cPFXZyuLTAARvcELBKAwLKUYB8AymqR8EoGAWjYCQAAPjnVzP7ApOfAAAAAElFTkSuQmCC","orcid":"","institution":"Ibn Sina Hospital, Mohammed V University","correspondingAuthor":true,"prefix":"","firstName":"MOHAMED","middleName":"MOUNIR","lastName":"NESNASSI","suffix":""},{"id":489380716,"identity":"d1e2628e-e053-495e-b7a6-f74bd28a6869","order_by":1,"name":"Asmae Benssiedd","email":"","orcid":"","institution":"Ibn Sina Hospital, Mohammed V University","correspondingAuthor":false,"prefix":"","firstName":"Asmae","middleName":"","lastName":"Benssiedd","suffix":""},{"id":489380717,"identity":"72ae15a7-f8e9-4055-aeca-9183294f11d4","order_by":2,"name":"Inasse Bargach","email":"","orcid":"","institution":"Ibn Sina Hospital, Mohammed V University","correspondingAuthor":false,"prefix":"","firstName":"Inasse","middleName":"","lastName":"Bargach","suffix":""},{"id":489380718,"identity":"43cbd5c8-569b-45c1-ba18-5513e6bd5c7c","order_by":3,"name":"Siham Hallab","email":"","orcid":"","institution":"Ibn Sina Hospital, Mohammed V University","correspondingAuthor":false,"prefix":"","firstName":"Siham","middleName":"","lastName":"Hallab","suffix":""},{"id":489380719,"identity":"94d274cd-7e86-4487-8c1a-17e3153765de","order_by":4,"name":"Safae Hilal","email":"","orcid":"","institution":"Ibn Sina Hospital, Mohammed V University","correspondingAuthor":false,"prefix":"","firstName":"Safae","middleName":"","lastName":"Hilal","suffix":""},{"id":489380720,"identity":"edfeced6-9842-40ff-b39a-5d1a5c4ba2d1","order_by":5,"name":"Ibtissam Fellat","email":"","orcid":"","institution":"Ibn Sina Hospital, Mohammed V University","correspondingAuthor":false,"prefix":"","firstName":"Ibtissam","middleName":"","lastName":"Fellat","suffix":""},{"id":489380721,"identity":"65d9314d-f0ea-4582-a25e-1dce6b81aed4","order_by":6,"name":"Mohamed Cherti","email":"","orcid":"","institution":"Ibn Sina Hospital, Mohammed V University","correspondingAuthor":false,"prefix":"","firstName":"Mohamed","middleName":"","lastName":"Cherti","suffix":""}],"badges":[],"createdAt":"2025-07-09 23:38:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7087630/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7087630/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s43044-025-00687-3","type":"published","date":"2025-09-18T15:56:57+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":87574693,"identity":"5464e35b-7c6c-4cda-9027-2b386d61023f","added_by":"auto","created_at":"2025-07-25 11:31:33","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":321727,"visible":true,"origin":"","legend":"\u003cp\u003eTransthoracic echocardiogram showing the left atrial mass.\u003c/p\u003e\n\u003cp\u003eA: Parasternal long axis showing the mass attached to the mitral valve. B: Parasternal long axis showing mitral regurgitation. C: Parasternal short axis showing the mass attached to the atrial septum. D: Apical 4 chamber view showing the mass mimicking an atrial myxoma.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7087630/v1/b5afdf4c3885cc3cd05047af.png"},{"id":87574694,"identity":"0dcc429a-f96e-453e-b150-4af281cedbf9","added_by":"auto","created_at":"2025-07-25 11:31:33","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":132521,"visible":true,"origin":"","legend":"\u003cp\u003emacroscopic aspect of the mass after its surgical removal.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7087630/v1/1a0aa38369838d76abec3c81.png"},{"id":91889771,"identity":"dfdd3bb8-77b4-4ab5-9e06-731613a94aa4","added_by":"auto","created_at":"2025-09-22 16:00:38","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":910187,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7087630/v1/beac6a5c-90d6-41d0-b73a-48b9da359ce9.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Left Atrial Fungal Mass Masquerading as Myxoma: The Importance of Histopathological Confirmation: A Case Report","fulltext":[{"header":"Introduction","content":"\u003cp\u003eInfective endocarditis (IE) remains a life-threatening disease despite advances in diagnostic and therapeutic strategies. According to the latest European Society of Cardiology (ESC) guidelines, echocardiography plays a pivotal role in the diagnosis of IE, with the detection of vegetations, abscesses, and new valvular regurgitations being major criteria for diagnosis [1]. Blood cultures and histopathological examination further confirm the diagnosis. Although bacterial pathogens remain the most common etiologic agents, fungal IE accounts for less than 10% of cases and is associated with a particularly poor prognosis [1,2]. Fungal endocarditis predominantly affects immunocompromised patients, those with prosthetic valves, or individuals with a history of intravenous drug use [2,3]. The clinical and imaging presentation of fungal cardiac masses can mimic benign primary tumors such as atrial myxomas, complicating the diagnostic process [4,5].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe report a rare case of left atrial fungal infective endocarditis in an immunocompetent patient, initially misdiagnosed as a myxoma, highlighting the importance of considering infectious etiologies in the differential diagnosis of intracardiac masses.\u003c/p\u003e"},{"header":"Case Presentation ","content":"\u003cp\u003eWe report the case of a 49-year-old male without medical history. He had a dental extraction performed 10 months prior. The patient presented with a two-month history of prolonged fever, headaches, night sweats, anorexia, weight loss, and fatigue. He also reported joint pain, mainly in the knees, and more recently palpitations and worsening dyspnea (NYHA class III).\u003cbr\u003e\u0026nbsp;Physical examination revealed a febrile state without cutaneous lesions. Cardiac auscultation detected a mitral regurgitation murmur. No signs of heart failure or embolic cutaneous manifestations were noted.\u003c/p\u003e\n\u003cp\u003eThe electrocardiogram showed a sinus rhythm at 85 beat per minute, a normal PR segment at 140 millisecond and normal QRS complexes without repolarization abnormalities. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTransthoracic Echocardiography (TTE) (Figure 1) found a heterogeneous mobile left atrial mass attached to the interatrial septum and mitral valve with a diameter of 35 mm. It also showed a moderate mitral regurgitation, a left ventricular ejection fraction (LVEF) at 50% and no signs of pulmonary hypertension or pericardial effusion.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLaboratory tests showed\u0026nbsp;\u003c/strong\u003eanemia (hemoglobin at 9.9 g/dL), leukocytosis (16,420/mm\u0026sup3;), elevated CRP (111.9 mg/L, decreasing to 26 mg/L with treatment), positive blood cultures for \u003cem\u003eStaphylococcus hominis\u003c/em\u003e and \u003cem\u003eStreptococcus acidominimus\u003c/em\u003e. Based on the presence of positive blood cultures and the new onset of mitral regurgitation, the diagnosis of cardiac infective endocarditis was evoked and the patient received intravenous antibiotics adapted to the culture sensitivities.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eHowever, the cardiac mass was not a typical image of valvular vegetation. Because of its typical location, the diagnosis of left atrial myxoma was evoked and the patient underwent surgery. The cardiac mass was successfully removed (Figure 2) with a macroscopic aspect of a mass of 6 g and measuring 25 mm by 15 mm, calcified and grayish yellow in color. The histological examination showed primarily fibrin-like material with fibrous organization and calcium rearrangement. Filamentous mycotic elements with spore-forming elements were also present.\u003c/p\u003e\n\u003cp\u003eThe final diagnosis was a fungal infective endocarditis. The patient received Amphotericin B 300 mg daily for two weeks. His clinical condition improved markedly, becoming afebrile with normalization of inflammatory markers and resolution of leukocytosis.\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003ePrimary cardiac tumors are rare, and myxomas represent the most common type, accounting for nearly half of them. Myxomas predominantly arise from the interatrial septum of the left atrium and typically present with obstructive cardiac symptoms, embolic events, or systemic constitutional symptoms such as fever and weight loss. Conversely, infective masses of the left atrium, particularly fungal infections, are extremely rare and often under-recognized. Fungal masses in the left atrium may clinically and radiologically mimic myxomas, posing a significant diagnostic challenge [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAlthough myxomas are relatively frequent among cardiac masses, left atrial fungal infections are exceptionally rare, particularly in immunocompetent individuals without prosthetic valves or a history of intravenous drug use [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Fungal endocarditis represents less than 10% of all infective endocarditis cases, with \u003cem\u003eCandida albicans\u003c/em\u003e being the predominant pathogen [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. When infections do involve the atria, they are more frequently bacterial and localized to the endocardium or valves. Left atrial fungal masses have only been reported sporadically in the literature [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe diagnostic confusion arises when a myxoma displays atypical echocardiographic features. Classic myxomas are pedunculated, mobile, and attached to the fossa ovalis region of the interatrial septum. However, atypical myxomas may appear sessile, irregular, and broad-based, sometimes lacking the typical \"ball-valve\" motion and resulting in a more infiltrative appearance on echocardiography [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. These atypical characteristics overlap with those of thrombi and infective vegetations.\u003c/p\u003e\u003cp\u003eFungal infections of the left atrium typically appear on echocardiography as heterogeneous, poorly defined masses, sometimes associated with mural thrombus formation or adjacent tissue destruction [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Transesophageal echocardiography (TEE) is more sensitive than transthoracic echocardiography (TTE) for detecting vegetations and fungal masses [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Nevertheless, the absence of a stalk, the irregular shape, and rapid evolution of the mass may orient toward an infectious origin rather than a tumoral one [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eOn macroscopic examination, myxomas are generally gelatinous, polypoid, and well circumscribed, sometimes displaying areas of hemorrhage. In contrast, fungal masses are often friable, necrotic, and poorly circumscribed, sometimes appearing cystic or purulent [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eHistologically, myxomas are composed of scattered polygonal or stellate cells embedded in a myxoid stroma, without any evidence of organisms. In contrast, fungal masses show thrombotic material with infiltration of yeast and hyphal forms, which can be demonstrated by Periodic Acid-Schiff (PAS) staining or Grocott methenamine silver stain [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThus, histopathological analysis remains the gold standard for definitive diagnosis in such cases [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Despite appropriate antifungal treatment with amphotericin B, the prognosis of fungal endocarditis remains poor, often complicated by embolic events and sepsis [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn our case, the echocardiographic features strongly suggested the presence of a cardiac myxoma, given its relative frequency. However, the final diagnosis revealed a fungal mass, a much rarer and less well-known entity. This rarity can lead to delays in diagnosis and treatment, especially since fungal infective endocarditis requires more urgent surgical intervention than a myxoma due to its generally poorer prognosis if not managed promptly. Fortunately, surgery was performed early in our patient, resulting in a favorable outcome. The key takeaway from this case is that a fungal mass should be considered as a differential diagnosis of atrial myxoma, particularly in the presence of other signs suggestive of infective endocarditis.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThis case highlights the diagnostic challenge of differentiating between infective endocarditis and primary cardiac tumors when encountering atypical intracardiac masses. Left atrial fungal endocarditis remains exceedingly rare, especially in immunocompetent patients without prosthetic valves or intravenous drug use. The echocardiographic appearance mimicking an atrial myxoma led to surgical resection, which provided the definitive diagnosis through histopathological analysis. According to ESC guidelines, the management of fungal infective endocarditis requires a combination of antifungal therapy and surgical intervention to improve outcomes. Clinicians should maintain a high index of suspicion for infectious etiologies in cases of atypical intracardiac masses to guide timely and appropriate management.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eIE\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eInfective endocarditis\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eESC\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eEuropean Society of Cardiology\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eNYHA\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eNew York Heart Association\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eTTE\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eTransthoracic Echocardiography\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eLVEF\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eleft ventricular ejection fraction\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003eTEE\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eTransesophageal echocardiography\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003e\u003cb\u003ePAS\u003c/b\u003e\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ePeriodic Acid-Schiff\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eConsent for publication\u003c/h2\u003e\u003cp\u003eWritten and informed consent has been obtained from the patient to publish the case report.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e\u003cp\u003eNone.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eM.N. wrote the main manuscript text and A.B. and S.H. prepared the fgures. I.B., A.A., S.H. and I.F. contributed to the research. M.C. was the supervisor.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eHabib G, Lancellotti P, Antunes MJ, et al. 2015 ESC Guidelines for the management of infective endocarditis: The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC). \u003cem\u003eEur Heart J.\u003c/em\u003e 2015;36(44):3075\u0026ndash;3128. doi:10.1093/eurheartj/ehv319\u003c/li\u003e\n \u003cli\u003eEllis ME, Al-Abdely H, Sandridge A, et al. Fungal endocarditis: evidence in the world literature, 1965\u0026ndash;1995.\u0026nbsp;\u003cem\u003eClin Infect Dis.\u003c/em\u003e 2001;32(1):50-62. doi:10.1086/318452\u003c/li\u003e\n \u003cli\u003ePierrotti LC, Baddour LM. Fungal endocarditis, 1995-2000.\u0026nbsp;\u003cem\u003eChest.\u003c/em\u003e 2002;122(1):302-310. doi:10.1378/chest.122.1.302\u003c/li\u003e\n \u003cli\u003eBaddour LM, Wilson WR, Bayer AS, et al. Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications: A Scientific Statement for Healthcare Professionals From the American Heart Association.\u0026nbsp;\u003cem\u003eCirculation.\u003c/em\u003e 2015;132(15):1435-1486. doi:10.1161/CIR.0000000000000296\u003c/li\u003e\n \u003cli\u003eBayer AS, Bolger AF, Taubert KA, et al. Diagnosis and management of infective endocarditis and its complications. \u003cem\u003eCirculation.\u003c/em\u003e 1998;98(25):2936-2948.\u003c/li\u003e\n \u003cli\u003eRevankar SG, Sutton DA. Fungal infections of the cardiovascular system.\u0026nbsp;\u003cem\u003eCardiol Clin.\u003c/em\u003e 2003;21(4):657-674. doi:10.1016/S0733-8651(03)00046-9\u003c/li\u003e\n \u003cli\u003eGowda RM, Khan IA, Nair CK, et al. Cardiac myxoma: a clinical and echocardiographic profile.\u0026nbsp;\u003cem\u003eInt J Cardiol.\u003c/em\u003e 2003;91(3):215-219. doi:10.1016/S0167-5273(03)00087-0\u003c/li\u003e\n \u003cli\u003eRaut MS, Maheshwari A, Dubey S, et al. A rare presentation of fungal endocarditis mimicking left atrial myxoma.\u0026nbsp;\u003cem\u003eAnn Card Anaesth.\u003c/em\u003e 2017;20(2):253-256. doi:10.4103/aca.ACA_110_16\u003c/li\u003e\n \u003cli\u003eGarc\u0026iacute;a-Cabrera E, Fern\u0026aacute;ndez-Hidalgo N, Almirante B, et al. Fungal endocarditis: the ICE prospective cohort study.\u0026nbsp;\u003cem\u003eClin Infect Dis.\u003c/em\u003e 2012;54(4):583-592. doi:10.1093/cid/cir850\u003c/li\u003e\n \u003cli\u003ePasha AK, Lee JZ, Low SW, et al. Fungal endocarditis: Update on diagnosis and management. \u003cem\u003eAm J Med.\u003c/em\u003e 2016;129(10):1037-1043. doi:10.1016/j.amjmed.2016.05.035\u003c/li\u003e\n \u003cli\u003eButany J, Nair V, Naseemuddin A, et al. Cardiac tumours: diagnosis and management. \u003cem\u003eLancet Oncol.\u003c/em\u003e 2005;6(4):219-228. doi:10.1016/S1470-2045(05)70093-0\u003c/li\u003e\n \u003cli\u003eEvangelista A, Gonzalez-Alujas MT. Echocardiography in infective endocarditis.\u0026nbsp;\u003cem\u003eHeart.\u003c/em\u003e 2004;90(6):614-617. doi:10.1136/hrt.2003.028712\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"the-egyptian-heart-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"tehj","sideBox":"Learn more about [The Egyptian Heart Journal](https://tehj.springeropen.com)","snPcode":"43044","submissionUrl":"https://submission.springernature.com/new-submission/43044/3","title":"The Egyptian Heart Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Infective endocarditis, Fungal cardiac mass, Fungal infective endocarditis, Left atrial myxoma","lastPublishedDoi":"10.21203/rs.3.rs-7087630/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7087630/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eBackground\u003c/b\u003e\u003c/p\u003e\u003cp\u003eInfective endocarditis (IE) remains a serious and potentially life-threatening condition. Fungal infective endocarditis is a rare form of endocarditis that occur in immunodeficient patients. Atrial myxoma are a common cause of cardiac tumors in the left atrium. However, infective endocarditis is a differential diagnosis of cardiac masses in general and atrial myxoma particularly.\u003c/p\u003e\u003cp\u003e\u003cb\u003eCase summary\u003c/b\u003e\u003c/p\u003e\u003cp\u003eA 49-year-old male with subacute infective endocarditis presentation underwent an echocardiogram examination that showed a left atrial mass with features of atrial myxoma. However, the histological examination after surgical removal of the mass showed a fungal mass.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThis case shows that a fungal infective endocarditis may present with a cardiac mass sharing typical features with left atrial myxoma. It also shows the importance of histological examination for the final diagnosis and a prompt treatment.\u003c/p\u003e","manuscriptTitle":"Left Atrial Fungal Mass Masquerading as Myxoma: The Importance of Histopathological Confirmation: A Case Report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-25 11:31:28","doi":"10.21203/rs.3.rs-7087630/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-24T18:52:02+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-24T12:51:49+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"64206579268759061766605973748769368","date":"2025-07-24T12:27:21+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-23T15:22:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"207846114605070893739552944714051179341","date":"2025-07-22T20:44:25+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-20T19:57:37+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-15T03:30:28+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-15T03:29:51+00:00","index":"","fulltext":""},{"type":"submitted","content":"The Egyptian Heart Journal","date":"2025-07-09T23:34:33+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"the-egyptian-heart-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"tehj","sideBox":"Learn more about [The Egyptian Heart Journal](https://tehj.springeropen.com)","snPcode":"43044","submissionUrl":"https://submission.springernature.com/new-submission/43044/3","title":"The Egyptian Heart Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f45993c1-e041-4344-9d36-46bee10c4295","owner":[],"postedDate":"July 25th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-09-22T15:58:15+00:00","versionOfRecord":{"articleIdentity":"rs-7087630","link":"https://doi.org/10.1186/s43044-025-00687-3","journal":{"identity":"the-egyptian-heart-journal","isVorOnly":false,"title":"The Egyptian Heart Journal"},"publishedOn":"2025-09-18 15:56:57","publishedOnDateReadable":"September 18th, 2025"},"versionCreatedAt":"2025-07-25 11:31:28","video":"","vorDoi":"10.1186/s43044-025-00687-3","vorDoiUrl":"https://doi.org/10.1186/s43044-025-00687-3","workflowStages":[]},"version":"v1","identity":"rs-7087630","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7087630","identity":"rs-7087630","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}