A Rare Intra-Atrial Cyst of Vascular Origin

Intra-atrial cysts are rare and often mistaken for neoplastic lesions. Vascular-origin cysts are even more uncommon. Limited genetic data hamper understanding of their pathogenesis and management. A 64-year-old man was referred for evaluation of an incidentally detected right atrial mass. Echocardiography suggested a hemorrhagic cyst. Surgical excision and histopathology confirmed a vascular malformation, with CD34 and smooth muscle actin positivity, elastic fibers demonstrated on special staining. Genetic testing revealed a pathogenic TSC2 mutation. The patient underwent successful mass resection and tricuspid annuloplasty with uneventful recovery. This case highlights a rare intra-atrial blood cyst associated with TSC2 mutation, suggesting a genetic basis for vascular malformations. TSC2 screening may help differentiate benign from malignant cardiac lesions, especially those with hemorrhagic features. In selected cases, image-guided aspiration could be a less-invasive alternative to surgery. TSC2 genetic testing may improve diagnosis and guide treatment strategies for atypical cardiac vascular lesions.