Abstract
Background The unilateral fetal variant of the posterior cerebral artery (FPCA) is characterized by the congenital absence of the P1 arterial segment. The artery of Percheron (AOP) is an uncommon vascular variant, in which a single dominant thalamoperforating arterial trunk arises from one P1 segment, bifurcates, and provides bilateral supply to the paramedian thalami and rostral midbrain. Case Presentation This is a retrospective case study of a 37-year-old man with multiple lifestyle risk factors (chronic marijuana and tobacco abuse), who suffered a thalamomesencephalic stroke, rapidly worsening to comatose state. After restoration of consciousness, he clinically manifested with left paramedian midbrain syndrome. Imaging demonstrated an asymmetric paramedian thalamic infarction with mesencephalon extension, patency of the basilar, vertebral arteries, and left PCA and right-sided FPCA, respectively. Left-sided thalamoperforating arterioles were not differentiated; AOP was inferred. Neither evident clinical source of embolus nor prothrombotic states were found. Mobile cardiac telemetry and transesophageal echocardiography were not available. The diagnosis was established too late for thrombolytic treatment. Anticoagulation was indicated during the acute and subacute stages, followed by low dose of antiplatelet. Discussion This uncommon cerebrovascular configuration (FPCA+AOP) might be the fourth case described in the literature. Sustained rehabilitation and abstinence from tobacco and cannabis led to favorable outcomes.
Highlights
The unilateral fetal variant of the posterior cerebral artery (FPCA) is characterized by the congenital absence of the P1 arterial segment
The case reported depicts a peculiar association of two vascular variants of the posterior cerebral circulation: a right-sided FPCA and an inferred artery of Percheron (AOP) emerging from the precommunicating segment (P1) of the left PCA, complicated with ischemic stroke, with fluctuations in consciousness [19], and reversible state of coma [20,21,22,23,24], in a complex chronic toxicological context, and a challenging etiopathogenic diagnosis
Punctilious morphology studies focusing the diversity of the thalamoperforating arteries (TPAs) indicated that AOP frequency across relevant cadaveric studies performed on unselected adult brains was variable (7.0–11.7%, Table 1) [7,8,9,10,11,12,13,14,15,16,17]
Summary
The vascular anatomy of the posterior circulation is complex and variable. Autopsy studies and structural imaging scans have detected normal anatomical variations in the morphology of the circle of Willis (incomplete circle, asymmetrical with duplication, absence or fusion of components, and fenestrations), are present in 48–58% of the general population [1,2,3,4], and arise during fetal development. Posterior TPAs arise from the superior, posterior, or posterosuperior surfaces of P1 Their morphological diversity and branching patterns, with multiple variations and complex courses, were subject of autopsy studies [7,8,9,10,11,12,13,14,15,16,17] and structural imaging scans [18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37], respectively. Occlusion of this uncommon arteriole results in a characteristic pattern of bilateral thalamic infarcts with or without mesencephalic involvement
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