Delayed white matter lesions after mechanical thrombectomy for large vessel occlusion stroke: Two case reports and...

Mechanical thrombectomy (MT) is performed for large-vessel occlusion (LVO) stroke. However, only a few cases of delayed white matter lesions (WMLs) have been reported after successful recanalization with MT. We present two cases of delayed WMLs despite symptomatic improvement after MT.

Case 1: An 81-year-old woman was diagnosed with ischemic stroke due to acute left internal carotid artery (ICA) occlusion. Complete recanalization was achieved after MT. The patient was discharged on Day 7 without neurological deficit. On Day 30, she was readmitted due to aphasia and right-sided paralysis, which progressively deteriorated over 2 weeks. Magnetic resonance imaging (MRI) diffusion-weighted imaging (DWI), and fluid-attenuated inversion recovery (FLAIR) images revealed hyperintense WMLs in the left anterior circulation territory, despite the left ICA patency. Her symptoms gradually improved to the modified Rankin scale (mRS) 1 with 6 months of rehabilitation. Case 2: An 84-year-old man was diagnosed with an ischemic stroke due to acute left middle cerebral artery (MCA) occlusion. Successful recanalization was achieved after MT. He was transferred to a rehabilitation hospital on Day 26, with mRS 1. However, on Day 52, the patient was readmitted because of gait instability that lasted for several days. MRI DWI and FLAIR images showed hyperintense WMLs in the left MCA territory despite the left MCA patency. On Day 96, he was finally transferred to the rehabilitation hospital at mRS 2 after another MT for another LVO stroke.

We encountered two cases of delayed WMLs after successful recanalization with MT. Careful follow-up is required even after symptomatic improvement.