小児脳腫瘍—統計的考察

BRAIN TUMORS OF CHILDREN

I．はじめに

　小児がんは，その治療が，いま，わが国では大きな医療上の問題となつているばかりではなく，小児は可能性に満ちた次代のにない手であり，小児がん患者の親の精神的な苦悩は測り知れず，さらにまた，治療に要する経済的負担は，いまや大きな社会問題となりつつある。

　昭和43年11月には，わが国で「がんの子供を守る会」ができ，昭和44年1月1日から，小児がんの全国登録が行なわれるようになり，ようやく，わが国における小児がん患者の実態が明らかにされつつある。ところが，小児がんの中で，脳腫瘍が重要な部分を占めていることがわが国では意外に見過ごされている傾向にあるのは残念なことである。わが国においても，脳腫瘍は小児がんの中で多く，例えば，昭和47年の小児がん登録数^15）を，がんの種類別にみると，脳腫瘍（129例，11.2％）は白血病（524例，45.4％）に次いで第2位であり，また，小児悪性固型腫瘍の発生部位別の順位をみても，昭和44年から昭和47年まで，脳がいずれも第1位を占めている。

　そこで，小児がんの中で，脳腫瘍は忘れてはならない重要なものであることを改めて強調するとともに，小児脳腫瘍の今後の治療の一助ともなるよう，われわれが1938年から現在まで経験した15歳未満の小児脳腫瘍について，種々の面から考察を加えたいと思う。今回はまず，小児脳腫瘍の統計的事項について述べたい。

The statistic analysis was made on 544 cases of brain tumors occurring in children up to the age of fifteen. The outstanding features are as follow: The incidence of brain tumors of children among whole brain tumors is 17.7%.

The sex distribution is slightly preponderant in male;the ratio is 1.1:1.O. But in cases below the age of six, it is more frequent in female; the ratio is 1.3:1.0. The tumors which occur considerably in favour of male are pinealomas, choroid plexus papillomas and teratomas and the relative preponderance in male is found in medul-loblastomas, glioblastomas, ependymomas and pitui-tary adenomas. On the other hand, the tumors which occur in favour of female are primary sarcomas, astrocytomas and skull tumors.

Comparing with adults, more common brain tumors in children are gliomas and congenital tumors, and less common are neurinomas, menin-giomas, pituitary adenomas and metastatic tumors. Among gliomas, medulloblastomas, spongioblasto-mas, ependymomas, pinealomas and pituicytomas are more common and glioblastomas, astroblastomas and oligodendrogliomas are less common in children.

In our series, pinealomas and congenital tumors especially for craniopharyngiomas and teratomas are considerably prominent and astrocytomas are less frequent as compared with the foreign litera-tures.

As for the location of the tumors, there is the relative preponderance of infratentorial over supra-tentorial growths between two to ten years of the age. But the incidence of infratentorial growths as whole is 50.7%. The tumors are also apt to be situated along the central neural axis except in cases less than one year of the age where the tumors are prone to deviate laterally.

In children, the tumors are situated more fre-quently in the cerebellum (30.6%) or the brain stem (22.2%), but the tumors of the cerebral hemi-sphere (14.0%) are relatively less common and those of the cerebellopontine angle (1.0%) are ex-tremely rare.

The location of the tumors is confined around the lateral or 3 rd ventricle in cases less than one year of the age, and the cerebellar tumors among infratentorial tumors and the sellar or chiasmal tumors among supratentorial tumors occupy about half of the cases between two to ten years of the age, and the favourite location is cerebral hemisphere or pineal region in cases over ten years of the age.