舌骨の反復的な刺激により発症した頚動脈狭窄症の1例

A Case of Carotid Artery Stenosis Associated with Repetitive Stimulation of the Hyoid Bone

Ⅰ．はじめに

　脳梗塞を来す原因は，喫煙，飲酒などの生活習慣，高血圧，脂質異常症，糖尿病，心疾患，抗リン脂質抗体症候群をはじめとした膠原病，プロテインC/S欠損症などの血液疾患など多岐にわたる．今回われわれは，生来健康で脳血管障害の家族歴を有さない若年男性において，頚部頚動脈狭窄症が原因で発症した脳梗塞の症例を経験した．既往歴を有さず，血液検査も異常を認めず，頚動脈狭窄症の原因として内科的疾患は否定的であった．画像所見から舌骨大角が頚動脈に接している所見を認め，解剖学的位置関係が頚部頚動脈狭窄症に関与している可能性が示唆された．舌骨と頚部頚動脈の接触が虚血性脳血管障害の原因とされた報告は，われわれが渉猟し得た限りでは8例認めた．非常に稀な症例であると考えられたため，若干の文献的考察を加えて報告する．

　A　40-year-old man presented with left-arm weakness, facial palsy, and dysarthria. Magnetic resonance imaging（MRI）revealed acute-stage cerebral infarction in the internal watershed area of the right hemicerebrum and MR angiography（MRA）demonstrated 56% stenosis of the right common and internal carotid arteries. Computed tomography（CT）scan showed no calcification and a stenotic lesion of the right common carotid artery, adjacent to the prolonged greater horn of the right hyoid bone. Because no other causes were found for the cerebral infarction, the compression of the stenosis of the right carotid artery was suspected as the cause of the cerebral infarction. Carotid arterectomy was performed five months after onset. Intraoperative finding showed tight adhesion between the carotid sheath and the adventitia of the carotid artery. Pathological findings showed a proliferation of fibroblast cells in the resected plaque.

　Common or internal carotid artery stenosis related to compression from the hyoid bone is rare. These cases hold a potential for tight adhesion around tissues. Therefore, in cases of prolonged hyoid bone, increased attention should be given to the operative procedure.