脳包虫症の一手術経験例

CEREBRAL ECHINOCOCCOSIS WITH A CLINICAL CASE REPORT

I．緒言

　わが国における包虫症，特に多房性包虫症は昭和12年，礼文島出身の小樽の一女性肝腫瘍摘出標本から証明せられてより，ひき続いて礼文島在住者に80数名の集団発生がみられ，さらに昭和40年秋からは新たに根室市において7人の患者発生が報告され，地方病として疫学的にもその対策は重要課題となつている。

　包虫症の発生は，直接・間接に母虫の固有宿主である犬，きつね，さらに中間宿主とされるねこ，ねずみ，ひつじ，ぶたなどの家畜を介してその卵子を摂取することが原因となるが，人体に寄生する場合の大部分は肝包虫症として肝臓に寄生するものであり，まれに肺・心・骨・腎などにも寄生しうるが脳に転移することはきわめてまれとされている。

Hydatid disease, when it's infection occurs in hu-man being, usually affect as liver echinococcosis and it's cerebral metastasis is quite uncommon even in endemic zone.

The presented case, 33 yrs. of house-wife whose living adress was Rebun Island in northern part of Japan, represents the second case operated upon for cerebral echinococcosis in Japan.

Several discussions has been performed about cer-ebral echinococcosis here in this report and the fol-lowing points were stressed in particular.

1) Echinococcosis should be considered in dis-tinguishing into two groups, i. e. Echinococcus multilocularis and Echinococcus granulosus. There is obvious differences between these two groups in their characteristics. Main differential characteristics were summerized in Table 2.

2) As to the frequency of affected organs in hu-man body, liver is the highest frequency of about 70% and then lung, heart, kidney, bone and spleen in order. Brain shows the lowest frequency ratingbetween 0.2% and 2.0% in whole human echinococ-cosis.

3) The cause of rarity of cerebral echinococcosis can be disclosed with considering the pathogenesis of the disease in human being. The infected embryo will implant into mesenteric lymph nodes and the subserosal lobulus of liver at first. According to the size of embryo, it being usually impossible to pass the capillary barrier or liver and lung and hard to pour into general blood circulation. So that the possibility of the trasferring of embryo to brain via blood stream become very few.

4) Clinical symptoms of the cerebral echinococ-cosis are quite similar as cystic glioma and differ-ential diagnosis shall be entirely difficult from it's clinical symptoms only.

5) Besides clinical symptoms, E. E. G., P. E. G. and C. A. G. are useful as diagnostic procedure for cer-ebral echinococcosis and among which the C. A. G. is the most advisable to perform by it's safer and obtaining conclusive value in diagnosis of this disease.

6) No effective medical treatment for echinococ-cosis is available and surgical removal of tumor is the only advisable one for the disease at present time, However, the value of surgical intervention shall be spoiled and sometimes impossible to perform the removal itself by deep location, multiple occur-rence and too huge size of tumor.

7) Although early diagnosis and early surgical treatment is very important to improve the prognosis of the disease, the majority of patients will be di-agnosed generally in late stage because of slow and gradual progression of the disease. Therefore, ef-fective surgery in early stage necessary for improve-ment of prognosis is usually rare and preventive measures should he done not only in endemic area but in neighbourhood.