前頭蓋窩硬膜動静脈瘻の2手術例―病理組織学的所見からみた発症機序について

Two Surgically Treated Cases with Dural Arteriovenous Malformation in the Anterior Cranial Fossa

Ⅰ．はじめに

　前頭蓋窩硬膜動静脈瘻は全硬膜動静脈瘻の6％と比較的稀であり¹⁾，その多くが頭蓋内出血で発症する．しかし非出血発症例は比較的少なく，その手術適応についてはいまだ議論が多い．今回，出血発症例と非出血発症例それぞれの手術例を経験し，それらの病理組織学的所見から発症病態と治療方針に関して示唆的な所見を得たので文献的考察を加えて報告する．

Dural arteriovenous fistulae(dAVF) in the anterior cranial fossa comprise about 6％ of all dAVFs,and is usually detected after intracranial hemorrhage. However,non-hemorrhagic symptoms are uncommon. We encountered two patients with hemorrhagic and non-hemorrhagic dAVF in the anterior cranial fossa. Both cases were successfully treated using craniotomy and histopathological examination was performed.

　A 71-year-old male experienced sudden onset of nausea and headache,followed by progression of left hemiparesis and disturbance of consciousness due to intracerebral and subdural hematoma in 2005. Intracerebral venous aneurysm adjacent to the intracerebral hematoma originated from the draining cortical red vein was identified and successfully treated by operation. Histopathological examination revealed disappearance of the internal elastic lamina and scant muscle tissue in the venous aneurysmal wall originating from draining cortical vein.

　A 69-year-old male suffered sudden onset of mild headache,followed by progression of bruits in 2005. MRI suggested dAVF in the left anterior cranial fossa. ¹²³I-IMP SPECT revealed an area of low perfusion in the left fronto-temporal region. Histopathological examination after surgical treatment revealed thickening of the intima and an indistinct lamina elastica interna,indicating progressive degenerative changes of the arterialized vein likely to result in hemorrhage.

　Surgical obliteration of fistulae is reasonable even in the dAVF of the anterior cranial fossa with ischemic onset.