Case Report: Three cases involving the use of endovascular intervention for artery of Percheron infarction with a unilateral fetal-type posterior cerebral artery.

Background: Occlusion of the artery of Percheron (AOP) in the context of a unilateral fetal-type posterior cerebral artery (fPCA) is a rare cerebrovascular etiology for bilateral thalamic infarction and is associated with distinctive clinical features. However, most of the previous literature on Percheron artery infarction consists of case reports without involvement of the fPCA. Here, we present and discuss the clinical characteristics of three cases of AOP infarction with a unilateral fPCA. Case presentation: All three patients presented with acute and profound impairment of consciousness and pupillary dysfunction. Neuroimaging [cranial magnetic resonance imaging (MRI) and computed tomography (CT)] revealed bilateral paramedian thalamic infarctions. Cerebrovascular studies confirmed a unilateral fPCA. Basilar artery occlusion was identified in Cases 1 (77-year-old woman) and 2 (62-year-old woman), while Case 3 (68-year-old man) exhibited severe stenosis of the left posterior cerebral artery (PCA) P1 segment. All three patients had large vessel lesions with an onset within 6 h. All patients underwent endovascular treatment without perfusion examinations. Outcomes were poor in Cases 1 and 3, while Case 2 showed neurological improvement. Conclusion: AOP infarction, although rare, warrants suspicion in patients presenting with an acute impairment of consciousness, pupillary abnormalities, and vertical gaze palsy, particularly in the absence of prominent limb weakness. The presence of a unilateral fPCA provides a critical diagnostic clue when bilateral paramedian thalamic infarction is confirmed radiologically (with or without midbrain involvement). Early neuroimaging, particularly MRI, is paramount for timely diagnosis. Although endovascular therapy may benefit selected cases, the overall prognosis remains guarded.