Fetal posterior cerebral artery infarction due to carotid dissection: a case report

Fetal posterior cerebral artery is an anatomical variant that occurs in 23-29% of the population. In this variant, posterior circulation, especially to the occipital lobe and mesencephalon, is provided by the posterior communicating artery. Whether fetal posterior cerebral artery constitutes a risk factor for ischemic stroke is still controversial. Our aim was to describe an exceptional case of ischemic stroke due to internal carotid artery dissection in a patient with fetal posterior cerebral artery anatomical variant.

A 46-year-old North African male patient presented to the neurology department of the National Institute Mongi Ben Hmida of Neurology, Tunis-Tunisia, 24 hours from acute-onset slurred speech, weakness, and impaired sensation in the left upper and lower limbs, as well as impaired visual field. His medical history was significant for hypertension with poor medication adherence. No history of recent trauma was reported. Neurological examination noted dysarthria, left hemiplegia with tactile hemihypoesthesia, left homonymous hemianopia, and right Horner's syndrome. National Institutes of Health Stroke scale score at admission was 20, with modified Rankin's scale at 4. Brain magnetic resonance imaging and magnetic resonance arteriography were performed at 24 hours from symptom onset, and showed radiological aspect compatible with ischemic stroke in posterior cerebral artery territory in fetal posterior cerebral artery configuration due to right extracranial and intracranial internal carotid artery dissection. Treatment with acenocoumarol 3 mg/day and atorvastatin 40 mg/day was implemented with significant improvement at 6-month follow-up.

Fetal posterior cerebral artery and internal carotid artery dissection are frequent separately, but their co-occurrence is exceptional. This report broadens the spectrum of internal carotid artery dissection and discusses the role of fetal posterior cerebral artery in ischemic stroke pathogenesis.