くも膜嚢腫に先天性頭蓋骨欠損を伴った1例

A Case of Congenital Skull Defect Complicated with Arachnoid Cyst

I．はじめに

　くも膜嚢腫は中頭蓋窩に好発し，中頭蓋窩の拡大，特に側頭骨の菲薄化・突出を伴うことが多いが，今回われわれは，中頭蓋窩くも膜嚢腫に先天的な頭蓋骨欠損を伴った稀な症例を経験したので，発生機序・治療に関する考察を加えて報告する．

A 3-month-old boy was referred to our hospital with left temporal bone defect and bulging skin. Theskull defect had been recognized since birth. There was no family history of any congenital anomaly andhis physical development was normal for his age. His bulged left temporal region was covered by normalskin and a skull defect measuring 2×2cm in size was palpated at the center. CT scan revealed skull defectat the pterion accompanied with widening of the middle cranial fossa. Arachnoid cyst of the middle cranialfossa was also suspected. The skull defect gradually enlarged and especially on crying the left temporalskin bulging became more marked. The bone edge of the defect was thin and was deflected outward. Theoperation was planned and performed at the age of 11 months. After excision and fenestration of thearachnoid cyst, cluraplasty and cranioplasty were performed using split-thickness calvarial bone graft. Split-ting the frontal calvarial bone suitable for the defect, the outer table was returned to the donor site, andthe inner table was fixed into the defect. Follow-up CT one year after surgery revealed a satisfactorycosmetic result and no bone resorption. Split calvarium cranioplasty is considered to be even more usefulin an infant.