胸椎硬膜外に発生した血管脂肪腫の2例―文献的考察を加えて

Thoracic Spinal Epidural Angiolipoma. Report of Two Cases and Review of the Literature

　血管脂肪腫は四肢末梢皮下組織や筋肉内にしばしば発生するが，脊柱管内発生は稀で全脊髄腫瘍中0.14～1.2％とされる．今回われわれは脊柱管内発生の硬膜外血管脂肪腫を2例経験した．画像診断では，MRI像が特徴的でT1強調像で等信号，T2強調像で高信号，ガドリニウム造影で増強される紡錐状の腫瘤像を呈する．2例とも脊髄症状に対し椎弓形成術および腫瘍全摘出術を施行し経過良好である．硬膜外血管脂肪腫は稀な疾患であるが，胸部脊髄症を来す鑑別疾患として念頭に置く必要性がある．治療は外科的摘出術が原則とされ，全摘・亜全摘ともに予後良好である．

　Spinal angiolipomas are uncommon benign neoplasms composed of a mixture of mature lipocytes and abnormal blood vessels.　They account for only 0.14―1.2% of all spinal tumors.　We report two cases in a 64-year-old woman and a 65-year-old man with thoracic myelopathy secondary to spinal angiolipoma.　Magnetic resonance imaging revealed isointensity on T1-weighted images, hyperintensity on T2-weighted images, and enhancement after gadolinium administration.　Laminoplasty was performed to resect the tumor, and the postoperative course was uneventful and associated with neurologic improvement.　Histopathological examination of the resected tumors revealed angiolipomas.　Although extremely rare, thoracic spinal epidural angiolipoma should be considered in the differential diagnosis of thoracic spinal lesions.　The prognosis after surgical management is favorable.