Blood-filled cysts (BFCs) are considered benign and often asymptomatic, most originate from congenital. However, BFCs of the heart valves are common at autopsy in infants but rare in adults. We report the case of an adult female who presented with a solitary complaint of chest distress on exertion, which led to the discovery of an intracardiac cystic mass on the anterior tricuspid leaflet. A single surgical intervention was sufficient to remove the resected cystic mass. Our case is the first to report a highly unusual blood-filled cyst on the anterior tricuspid leaflet in an adult.