胸椎高位に発生した無症候性epidermoid cyst成人例の1例

Epidermoid Cyst of the Thoracic Spine. Case Report

　症例は74歳の女性で，腰痛，間欠性跛行を呈しL4すべり症の手術目的で入院した．術前の脊髄腔造影で，偶然にTh10椎体後面に騎跨状陰影欠損を認めた．MRIではT1強調像で低信号，T2強調像で高信号を呈し，脊髄の圧迫は著明であった．Gd-DTPAでrim-enhanceを認めた．理学所見では胸腹部の感覚異常，下肢腱反射亢進，病的反射もなく無症候性の脊髄腫瘍と診断し，腫瘍摘出とL4/5の部分椎弓切除術を行った．病理診断はepidermoid cystであった．現在，術後2年経過し再発はない．再発に対する長期の経過観察が必要である．

　Intradural extramedullary epidermoid cysts are rare tumors, especially in the thoracic spine. We report a case of asymptomatic epidermoid cyst of the thoracic spine. A 74-year-old woman came to our hospital because of low back pain and numbness in both legs. A diagnosis of L4 degenerative spondylolisthesis was made, and medication was prescribed, but her symptoms were worsened by intermittent claudication. Cupping at the Th10 level was revealed by myeloglaphy, and magnetic resonance imaging of thoracic spine showed a 2-cm intradural, extramedullary mass at the Th10 level associated with spinal cord compression. However, no Babinski responses or hyperactive reflexes of the lower extremities were elicited. The tumor was considered asymptomatic. A Th10 and Th11 laminectomy with complete removal of the intradural mass and partial L4/5 laminectomy were performed. The final histological diagnosis was epidermoid cyst. The primary treatment of epidermoid cyst of the thoracic spine should be complete surgical resection followed by serial follow-up imaging examinations.