Small carotid thrombus and minimal stenosis causing repeated embolic strokes.

Despite current developments in neuroradiology, the sources of infarctions go undiagnosed in 28% of cases. An embolic source in the setting of minimal stenosis at the carotid bifurcation has rarely been reported. The authors report a previously healthy 48-year-old woman, without any risk factors for cerebrovascular events, sustained multiple cerebral infarctions in the right anterior and middle cerebral artery territory. Repeated imaging of the heart and cerebral vessels missed a very small abnormality arising from the posterior wall of the internal carotid artery, until it was diagnosed by computed tomographic angiography. This is problematic because by North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria, minimal stenosis essentially excludes the carotid artery as an embolic source. Despite maximum antiplatelet and anticoagulation therapy, she continued to have neurological deteriortation by progression of her strokes. She underwent standard carotid endarterectomy and sustained no new embolic phenomena. Histopathological examination showed an endothelial hyperplasia with organizing thrombus, which on the posterior wall of the internal carotid artery, is likely a hemodynamically induced on top of preexisting atherosclerotic plaque.