Cortico–hypothalamic pathway of Horner syndrome derived from isolated lenticulostriate stroke

Backgrounds Horner syndrome presents with ipsilateral ptosis, miosis, and anhidrosis due to interruption of the oculosympathetic pathway. Patients with acute ischemic stroke may present with Horner syndrome, which may help locate the lesion. However, the underlying pathways involved in Horner syndrome caused by isolated lenticulostriate ischemic stroke remain unclear. Methods We screened consecutive patients with acute ischemic stroke admitted to the Second Affiliated Hospital of Guangzhou Medical University from 1 January 2020 to 31 December 2021, and searched for cases of isolated lenticulostriate strokes presenting with Horner syndrome. Strokes involving the brainstem or hypothalamus, or those caused by carotid dissection or carotid cavernous fistula were excluded based on neuroimaging and cerebrovascular examination. Results Among the 1706 acute stroke patients, three patients developed temporary or long-term Horner syndrome due to an ipsilateral lenticulostriate ischemic lesion. Diffusion-tensor imaging revealed disruption of an uncrossed pathway from Brodmann areas 3, 1, and 2 through the basal ganglia to the ipsilateral hypothalamus. Conclusion These findings suggest that Horner syndrome may be due to a disruption of an uncrossed cortico-basal ganglia-hypothalamic sympathetic pathway.