Aims: The etiology of stroke in young adults may be challenging. After preliminary investigations, a cause is not established in about one-third of patients. Cardiovascular embolism has been recognized as the cause of unexplained stroke or transient ischemic attack in a relevant number of young stroke patients. Materials and Methods: A 39-year-old right-handed woman was admitted to hospital with a left-side weakness of sudden onset. Her personal and family history were unremarkable except for several episodes of left arm weakness lasting for less than 10 minutes. On cranial magnetic resonance imaging, a right frontotemporal infarction was observed. Results: Laboratory work-up revealed normal clotting, thrombophilia and vasculitis screen. The transesophageal echocardiogram showed an atrial septal aneurysm with a large thrombus in the right atrium and spontaneous echo contrast inside the left atrium. The patient was started on anticoagulation. During the four-year follow-up she had no recurrence of stroke or transient ischemic attacks. Conclusions: An atrial septal aneurysm is a rare but well-recognized cardiac abnormality that is recently recognized as an occult cardiac source of cerebral embolism. Its association with spontaneous echo contrast presents a higher embolic risk.

Aims: The etiology of stroke in young adults may be challenging. After preliminary investigations, a cause is not established in about one-third of patients. Cardiovascular embolism has been recognized as the cause of unexplained stroke or transient ischemic attack in a relevant number of young stroke patients. Materials and Methods: A 39-year-old right-handed woman was admitted to hospital with a left-side weakness of sudden onset. Her personal and family history were unremarkable except for several episodes of left arm weakness lasting for less than 10 minutes. On cranial magnetic resonance imaging, a right frontotemporal infarction was observed. Results: Laboratory work-up revealed normal clotting, thrombophilia and vasculitis screen. The transesophageal echocardiogram showed an atrial septal aneurysm with a large thrombus in the right atrium and spontaneous echo contrast inside the left atrium. The patient was started on anticoagulation. During the four-year follow-up she had no recurrence of stroke or transient ischemic attacks. Conclusions: An atrial septal aneurysm is a rare but well-recognized cardiac abnormality that is recently recognized as an occult cardiac source of cerebral embolism. Its association with spontaneous echo contrast presents a higher embolic risk.