A case of lenticulostriate artery infarction presenting with peripheral type facial palsy.

An 82-year-old woman developed a droopy right eyelid with ipsilateral hemiparesis. Her ocular symptom was caused by weakness of the right frontalis, which is usually seen in patients with peripheral facial nerve palsy. However, head MRI showed acute cerebral infarction of the left lenticulostriate artery, and electroneurography did not detect damage to the right facial nerve. To explain the pathophysiology in this patient, asymmetrical bilateral cortex innervation to the right upper face was hypothesized. This case suggested that patients with some hemispheric strokes could develop upper facial weakness mimicking facial nerve palsy, and clinicians should pay attention to this potential pitfall in the differential diagnosis of facial nerve palsy.