Abstract
Blood cysts of the heart are rare benign tumors, usually involving the cardiac valves. They are found mainly in the first month of life and in children; and are rarely seen in adults. Here, we report a case of a blood cyst on the subvalvular apparatus of the mitral valve, which was incidentally discovered during chest computed tomography in a 47-year-old man. To the best of our knowledge, this is the first reported case of blood cyst of the heart in an adult in Korea.