Abstract
BACKGROUND: Mitral valve aneurysm is a rare structural abnormality characterized by a saccular protrusion of the mitral valve leaflet. The diagnosis of a mitral valve aneurysm can be challenging, especially when echocardiography fails to show a clear saccular appearance. CASE PRESENTATION: A 66-year-old male patient exhibited no symptoms but demonstrated echocardiographic findings indicative of a suspected cardiac tumor on the anterior mitral leaflet. Transesophageal echocardiography revealed nodular lesions on the anterior mitral leaflet, each measuring 11 × 5 mm. The findings also revealed mild mitral regurgitation. Intraoperatively, the lesions were identified as aneurysmal protrusions of the anterior mitral leaflet. Mitral valve repair was deemed unfeasible; therefore, mitral valve replacement was performed. CONCLUSION: The diagnostic challenge of mitral valve aneurysm, particularly in atypical cases, highlights the importance of thorough echocardiographic evaluation.