頚胸髄軟膜下脂肪腫の1例

A Case of Cervicothoracic Subpial Lipoma

Ⅰ．はじめに

　二分脊椎などの神経管閉鎖異常を伴わない脊髄軟膜下脂肪腫は稀な疾患であり，全脊髄腫瘍の1％以下と報告されている^1-5,7)．今回われわれは，外科的治療を施行し，歩行障害，感覚障害の改善が得られた頚胸髄軟膜下脂肪腫の1例を経験したため，報告する．

　We report the case of a 24-year-old woman with cervicothoracic subpial lipoma not associated with spinal dysraphism. She complained of back pain,gait disturbance,and sensory disturbance of the both lower extremities. MRI revealed a hyperintense mass lesion that was dorsolateral to the spinal cord in the intradural region between C7 and Th4 on both T1 and T2 weighted images. Axial T2 weighted images showed dorsal nerve roots passing through the mass. A thoracic laminectomy between Th1 and Th4 was performed. A yellowish subpial mass was found after the dura was opened,and the borderline between the tumor and the normal spinal cord was unclear. The mass was partially resected and intraoperative SEP monitoring data remained unchanged. Dural plasty using artificial dura was performed. Histological examination revealed mature adipose and connective tissues,a fact which was compatible with a diagnosis of lipoma. Postoperatively,no complications occurred. The patient's gait disturbance and hypesthesia of the right lower extremity slightly improved.

　Subpial spinal lipoma not associated with dysraphism is rare and accounts for only 1% of all spinal tumors. A slow ascending spastic monoparesis or paraparesis is a common initial symptom. However,once symptoms progress,further deterioration is rapid. Therefore,early surgical decompression and debulking of the subpial lipoma in patients with neurological abnormalities is recommended because most symptomatic patients do not improve after surgery.