Abstract
BACKGROUND: Intracardiac blood cysts rarely persist into adulthood and may lose their typical echolucent appearance when chronically hemorrhagic and organized. CASE SUMMARY: A 54-year-old woman presented with exertional dyspnea. Transthoracic echocardiography revealed a mobile left ventricular outflow tract (LVOT) mass (19 × 16 mm) causing severe dynamic obstruction (peak gradient 85 mm Hg) without a classic anechoic cavity. Three-dimensional transesophageal echocardiography demonstrated subvalvular chordal attachment. Multimodality imaging, including myocardial contrast echocardiography, cardiac computed tomography, and cardiac magnetic resonance, showed no enhancement, supporting an avascular benign cyst. Valve-sparing excision with mitral valve repair was performed. Histopathology confirmed a chronically organized blood cyst, with resolution of LVOT obstruction and symptoms. DISCUSSION: Atypical adult LVOT blood cysts may mimic tumors or vegetations; multimodality imaging can establish benignity and guide valve-preserving surgery. TAKE-HOME MESSAGE: Integrated multimodality imaging can establish benignity and support safe valve-sparing surgery in atypical LVOT cysts.