Radiotherapy as a Contributing Factor to Carotid Vasculopathy Leading to Tandem Internal Carotid-Middle Cerebral Artery Occlusion Stroke

A 64-year-old man with a history of p16-positive oropharyngeal squamous cell carcinoma treated with high-dose bilateral radiotherapy in 2017 presented with sudden-onset left-sided weakness, dysphasia, and homonymous hemianopia. Initial computed tomography and computed tomography angiography demonstrated complete right internal carotid artery (ICA) occlusion with a tandem right middle cerebral artery (M1) thrombus. Magnetic resonance imaging confirmed multiple acute infarctions within the right middle cerebral artery territory and watershed zones. He underwent urgent mechanical thrombectomy with angioplasty and stenting of the right ICA, achieving successful reperfusion. His medical history included hypertension, hypothyroidism, and previous smoking. This case highlights radiotherapy as a contributing factor to accelerated carotid vasculopathy and delayed large-vessel ischaemic stroke. It underscores the importance of long-term vascular surveillance in cancer survivors who previously received high-dose neck radiotherapy and demonstrates that mechanical thrombectomy with carotid stenting is a feasible treatment strategy in radiation-associated tandem vessel occlusion.