[A young adult with internal carotid artery occlusion during finasteride therapy: pathological findings from a thrombus retrieved by mechanical thrombectomy].

Androgenetic alopecia (AGA) is commonly treated with finasteride and minoxidil, which are both recommended as grade A therapies in the Japanese Dermatological Association guidelines. However, their association with thromboembolic events and ischemic stroke remains unclear. We report a 40-year-old man without apparent risk factors for stroke who developed acute ischemic stroke due to left internal carotid artery occlusion while taking finasteride (1 mg/day) and minoxidil (10 mg/day). Mechanical thrombectomy retrieved a dark red thrombus primarily composed of red blood cells and fibrin. This case represents a rare report of internal carotid artery occlusion with pathologically confirmed thrombus in a patient receiving these medications. Finasteride may promote hypercoagulability via androgen suppression-induced estrogen predominance, and minoxidil may contribute through blood pressure-lowering effects. Intravenous alteplase and thrombectomy were effective treatments, and discontinuation of the medications is recommended for secondary prevention.