手術当日術前塞栓術が有用であった充実性小脳血管芽腫の2例

Preoperative Embolization for Solid Cerebellar Hemangioblastoma on the Day of Surgery:Two Case Reports

Ⅰ．はじめに

　血管芽腫はWHO分類grade Ⅰの良性腫瘍であり，全頭蓋内腫瘍の1.5〜2.5%の発生頻度で，発生部位は小脳76%，大脳半球9%，脊髄7%，脳幹近傍5%と報告されている⁵⁾．小脳に発生するものが最も多く，全小脳腫瘍の10%を占める．血管芽腫は囊胞性（cystic type），および充実性（solid type）に分類され，充実性が約30%，囊胞性が約70%を占める¹²⁾．治療は全摘出が主軸となるが，脳動静脈奇形のごとく発達した血管があり，腫瘍に切り込むと大量の出血に難渋することになり，栄養動脈の処理と，周囲からの剝離による一塊摘出が原則である．ただし，手術に伴うリスクは，発生部位，充実性か囊胞性か，などにより異なる．特に，充実性小脳血管芽腫は囊胞性のものと比しhypervascularであること，また減圧のスペースの確保が困難であることから，摘出術の難度は高い⁹⁾．近年，髄膜腫など腫瘍血管の発達した頭蓋内腫瘍に対する術前塞栓術の有用性が報告されている¹¹⁾．一方，血管芽腫の術前塞栓術の報告は散見されるものの，その有用性は議論の余地がある．今回われわれは，充実性小脳血管芽腫の2例に対し，開頭腫瘍摘出術同日に液状塞栓物質n-butyl-2-cyanoacrylate（NBCA）による術前塞栓術を行い，手術摘出の確実性と安全性に有用であったと考えられたので，文献的考察を加え報告する．

　Surgical resection of solid cerebellar hemangioblastomas can be challenging because of the profuse blood supply and tight space. We report two cases of solid cerebellar hemangioblastomas treated via surgical resection with the aid of preoperative endovascular embolization on the day of surgery. Case 1：A 36-year-old woman presented with a two-month history of headache and vomiting. Magnetic resonance imaging（MRI）revealed a right cerebellar solid mass, mild hydrocephalus, and apparent peritumoral edema. Angiogram showed a highly vascularized mass, three feeding arteries from the superior cerebellar artery（SCA), and a dilated vein draining into the confluence. We performed preoperative embolization of the three feeders with 15% n-butyl-2-cyanoacrylate（NBCA). Final angiogram showed an absence of tumor staining. Tumor resection was performed on the same day, and gross total resection was achieved with no complications. Case 2：A 36-year-old man presented with a four-month history of headache and numbness in the left upper extremity. MRI revealed a right cerebellar solid mass with peritumoral edema. Angiogram showed a highly vascularized mass with two feeding arteries from the right SCA, one from the left posterior inferior cerebellar artery（PICA), and a dilated vein draining into the confluence. Preoperative embolization was performed with 15% NBCA, and complete devascularization was achieved. Tumor resection was performed on the same day, and gross total resection was achieved with no complications. In conclusion, preoperative embolization with NBCA on the day of surgery is a safe and effective adjunctive treatment for solid cerebellar hemangioblastoma.