Non-ischemic cerebral enhancing (NICE) lesions after extracranial carotid stenting: A case report

Non-ischemic cerebral enhancing (NICE) lesions are exceptionally rare complications of neuroendovascular procedures and have been reported predominantly after intracranial interventions, with only one previous case following extracranial carotid stenting. We report a second such case. A woman in her mid-thirties with inactive Takayasu arteritis underwent long-segment extracranial stenting of asymptomatic stenoses of the left common (CCA) and internal carotid (ICA) arteries using three overlapping stents. Eighteen days after the procedure, she developed new-onset headache; MRI showed a small left parieto-occipital hemorrhage and multiple ipsilateral NICE lesions. Serial MRI over 10 months demonstrated asynchronous NICE lesion behavior, with simultaneous emergence, regression, and persistence of ipsilateral and contralateral foci. Their non-ischemic morphology and the absence of clinical, laboratory, CSF, or vascular imaging evidence of active vasculitis argued against a Takayasu-related origin. Despite fluctuating lesion burden, she developed no persistent neurological deficits and required no long-term immunosuppressive therapy. Mild headaches and a one-day cluster of focal sensory seizures occurred, with no recurrence under low-dose lamotrigine. This case provides further evidence that NICE lesions are not confined to intracranial procedures and may also follow extracranial carotid stenting, showing highly variable lesion dynamics. The continued appearance of new lesions up to 308 days after stenting suggests persistent microembolization or delayed inflammatory manifestation of initially occult embolic deposits rather than a purely one-time periprocedural event. The divergence between radiological lesion burden and clinical severity further suggests that management should be guided primarily by the clinical course and that conservative management may be appropriate in clinically stable patients.