類上皮腫に対する外科的治療と長期治療成績

Long-Term Outcomes of Surgical Treatment for Epidermoid

Ⅰ．はじめに

　類上皮腫は，これまで，部分摘出とすれば高率に再増大し，術後の水頭症の合併も多いと考えられてきており，Yaşargilら⁹⁾やSamiiら⁶⁾に代表されるように，全摘出が勧められてきた．しかし，しばしば脳神経や血管との癒着が強い腫瘍であり，morbidityは決して低くはない．また，近年では残存する腫瘍の再増大率は比較的高くなく，増大する場合でもその増大速度は非常に遅いという報告が散見されるようになってきている⁷⁾．

　類上皮腫に対する当科の手術方針は，腫瘍被膜とその周囲のくも膜を可能な限り鋭的に剝離し，可及的摘出を原則としているが，剝離不能な場合はmorbidityを来さぬことを第一義とし，無理な摘出は控え意図的に亜全摘や部分摘出としてきた．

　今回，当科の類上皮腫に対する長期治療成績を検討したので，文献的考察を加え報告する．

　Objective: Surgical strategies for epidermoids in our department is that the tumor capsule and surrounding arachnoid membrane should be sharply dissected and resected as much as possible. However,if total resection is not possible,because of the danger of surgical morbidity,partial resection should be carried out. The present study reports on long-term outcomes of surgical treatment for intracranial epidermoid in our department.

　Methods: Since 1994, intracranial epidermoids have been resected in 13 patients in our department. The mean age at the time of surgery was 50.2 years and the mean postoperative follow-up period was 75.8 months. Surgical outcome, postoperative morbidity, Karnofsky Performance Status (KPS) during long-term follow-up, hydrocephalus, and regrowth rate were investigated.

　Results: Among the 13 patients, 5 underwent total resection, 5 subtotal resection, and 3 partial resection. No permanent morbidity occurred and KPS did not worsen postoperatively in any of the patients. Surgery for hydrocephalus was performed in 3 patients. However, hydrocephalus had been suspected before surgery in each patient. Regrowth occurred in 1 patient, showing malignant transformation 1 year after total resection. No regrowth during long-term follow-up was observed in the other 12 patients, and none showed exacerbation of KPS.

　Conclusion: The present study indicates that regrowth does not necessarily occur in patients with epidermoids. Although total resection is ideal,to avoid any surgical morbidity is even more important. Partial resection should be performed if total resection is impossible.