Tricuspid regurgitation due to blood cyst.

Cardiac blood cysts are confirmed by autopsies in stillbirths but rarely detected in adults. Although cardiac blood cysts are common in newborns, they disappear within a few months after birth. These cysts are blood-filled diverticula surrounded by endothelium. Their possible etiology is invaginations of atrial endothelium into the stroma of atrioventricular valves. Most blood cysts originate from the left side of the heart and are located on the atrioventricular valves. Complication is followed in very little cases, such as embolic stroke, valvular dysfunction, and ventricular outflow system obstruction. The blood cysts leading to complications should be removed surgically.