Abstract
Fetal and neonatal cardiac tumors are rare and often benign. Clinical presentation is primarily related to mass effect, pericardial effusion or arrhythmia. Prenatal detection can assist with risk assessment and inform optimal delivery plan and postnatal management. We report a fetus with a right atrial mass discovered in the third trimester. After successful surgical resection, pathology confirmed the mass to be a capillary-venous malformation, which are rare and challenging to diagnose. The true incidence of these vascular malformations within cardiac spaces is difficult to discern given the historic classification of numerous different vascular malformations under the umbrella term hemangioma.