横静脈洞と交通する先天性頭皮動静脈奇形の1例

Congenital Arteriovenous Malformation of the Scalp with a Drainage to the Transverse Sinus : a case report

I．はじめに

　頭皮の動静脈奇形（AVM）は，特徴的な外観により古くから知られているが，比較的稀な疾患である．なかでも頭蓋内と交通する先天性頭皮AVMは極めて稀で，これまでに3例の報告がみられるのみである^3,5）．われわれは，頭蓋内硬膜静脈洞と交通する先天性頭皮AVMを経験したので報告する．

Arteriovenous malformation (AVM) of the scalp is uncommon, and a subtype which has connectionwith the intracranial dural sinus is extremely rare. Only 3 cases have been reported. We present a case ofcongenital AVM of the scalp which was connected with the intracranial venous sinus.

A 27-year-old woman had been noted as having a pulsatile soft mass in the midline of the occipital re-gion since her birth. She visited our hospital because of pain and enlargement of the mass. The patient hadhad no history of trauma.

Physical examination revealed a pulsatile scalp mass in the midline of the occipital region, measuring 3.5×3.5×1cm. A loud bruit was ausculated. Tenderness was noted. The skin over the mass was slightly red-dish. No focal neurological deficits were noted.

Plain skull films demonstrated a round defect in the midline of the occipital bone. Magnetic resonanceimaging (MRI) demonstrated a subcutaneous mass with low signal intensity and an infratentorial masswith flow void. 31) CT angiograms demonstrated a subcutaneous vascular mass with a single large veindraining into the right transverse sinus. External carotid angiograms revealed a vascular lesion within thescalp with supply from the branches of the bilateral occipital arteries and the meningeal arteries. The niduspenetrated the skull and connected to a dilated varix, which had a draining vein shunting into the righttransverse sinus.

After embolization of the right meningeal feeding arteries, surgery was performed. The vascular lesionpenetrated the skull and the dura. The infratentorial mass was in the epiarachnoid space and was fed by asmall pial artery. The mass was excised completely after interruption of the pial artery and the drainingvein.

Postoperative course was uneventful. Histologically, the subcutaneous mass and infratentorial vascularmass were shown to be AVM and varix, respectively.