頭蓋内進展を来したnasal dermal sinus-cyst（NDSC）の1例

A Case of Nasal Dermal Sinus-cyst（NDSC）with Intracranial Extension

Ⅰ．はじめに

　Nasal dermal sinus-cyst（NDSC）は鼻部の皮膚に開口する皮膚洞を合併したdermoid cystに対して，Sessions（1982）が初めて提唱した名称である¹⁶⁾．本症のdermoid cystはしばしば頭蓋内に進展し，感染の原因になることから，診断確定後は早期の外科的摘出が推奨されてきた．しかし詳細な手術方法を記載した報告は少ない．今回われわれは頭蓋内に発生したdermoid cystと鼻根部に開口する皮膚洞を開頭術にて全摘出した症例を経験したので，文献的考察を加えて報告する．

　Nasal dermal sinus-cyst (NDSC) is a rare abnormality consisting of a dermal sinus opening at the nasal skin and dermoid cyst localized in the frontobasal area. A 2-year-old boy was admitted to our hospital due to swelling of the fronto-nasal regions with pus running from an orifice situated in the nasal skin. Bone-image CT and 3D-CT revealed bone defects within the frontal skull base. MRI demonstrated that a dermoid cyst centered in a bone defect was in contact with the dura of the frontobasal area, and a dermal sinus extending to the frontonasal skin could also be detected. Surgical resection was performed by frontobasal craniotomy. The dermal sinus was followed subcutaneously into the orifice of the nasal skin. A small skin incision was made and the sinus was then totally removed. The authors describe in detail this case of NDSC which extended to the intracranium, and review the literature regarding this abnormality.