Abstract WP476: Remarkable Hemorrhagic Imaging Manifestations Might Be Responsible for the Prominent Atrophy and Cognitive Decline in Sneddon Syndrome

Objective: Sneddon syndrome is a rare non-inflammatory arteriopathy affecting small and medium-sized arteries, characterized by a generalized livedo reticularis and recurrent ischemic stroke. Hemorrhagic stroke was reported in limited cases, but microbleeds and superficial siderosis were rarely issued, which might be underdiagnosed due to the limitation of technique. We aimed to investigate the hemorrhagic imaging features of Sneddon syndrome and explore the possible mechanism and clinical relevance. Methods: Clinical data and cerebral MR imaging including T2* sequence of 6 consecutive patients with Sneddon syndrome were reviewed. Results: The most common neurological manifestations were cognitive impairment and stroke attack(66.7%), followed by seizures(33.3%) and movement disorder(16.7%). Cerebral microbleeds were detected in all the patients on T2* sequence,four of whom presented more than 5 microbleeds.The majority of the microbleeds were predominantly cortical restricted and especially located in the cortical watersheds. Multiple superficial siderosis were identified and mainly involved cortical watersheds in 5 cases. Significant cerebral atrophy with prominent secondary white matter hyperintensities in bilateral cortical watersheds were also observed. Abnormal tortuous and multiple focal occlusion of bilateral distal MCA were shown in 1 patient by DSA. No stenosis of proximal segment of cerebral arteries was detected in all the patients. Conclusions: This is the first report illustrating abundant cortical microbleeds and superficial siderosis mainly involved the anterior and posterior cortical watersheds in Sneddon syndrome. The surprisingly identical topographic distribution of hemorrhagic lesions and the corresponding obvious atrophy suggest cerebral atrophy might be secondary to the microangiopathy related hemorrhagic lesions and further contribute to the neurological deficit, especially the early cognitive decline in Sneddon syndrome,although further investigation is needed to elucidate the precise underlying pathogenesis. These highlight cortical microbleeds and superficial siderosis located in cortical watershed and the secondary atrophy in youth might be highly indicative of Sneddon syndrome.