Intracardiac blood cysts are rare findings in daily clinical practice, which are usually congenital. They are generally located on cardiac valves and rarely found in adult ages. While some cardiac cysts are asymptomatic and undiagnosed, others may present with complications. We report a case of cyst attached to the mitral valve which remained silent until 82 years in a woman but diagnosed during evaluation of the etiology of a transient ischemic event in a 82-year-old woman