実験的脳膜肉腫の発生に関する組織病理学的・組織化学的研究

HISTOLOGICAL-AND HISTOCHEMICAL STUDIES ON THE HISTOGENESIS OF THE EXPERIMENTALLY PRODUCED MENINGEAL SARCOMA

I．はじめに

　脳膜腫（meningioma）は，脳腫瘍のうちグリオームについで第2位を占めているが，その組織発生については，まだ多くの問題を残している。脳膜の発生についても，中胚葉説と外胚葉説とがあり，それぞれの発生学的見地から脳膜腫を分類しているため余計に混乱をきたしているとも考えられる。たとえば，名称については，Penfield meningeal fibroblastomaといい，O．　T．　Baileyはara—chnoid cellが脳膜腫の源と汚えてarachnoblastomaなる名称を提唱しているごとくである^1）2）3）。さらに，脳膜の原発性肉腫にいたつては，Cushing　＆　Eisenhardt^4）らは脳膜腫から除外しており，他方，Globusはprimarysarcomatous meningiomaとしてこれに加えている。わが国でも稲葉^5）は，脳膜性間葉を起源とするもの（tumors of meningeal origin）として脳膜腫のカテゴリーに入れている。

　著者らは，20—methyicholanthreneの結晶針をマウスの脳内に埋没し，実験的に脳膜肉腫を生成し，生成途上の脳組織とともに，組織学的に，さらに核酸の組織化学をも加えて検索し，脳膜肉腫の組織発生の由来と機序について考察した。

The production of meningeal sarcoma was attem-pted by 20-Methylcholanthrene crystals that were implanted in the left parietal areas of 73 hybrid mice brains. Meningeal sarcomas developed in eleven mice. The survival periods were from 121 days to 238 days after implantation of carcinogenic sudstan-ce, and a ratio of induction was 35.5%.

The experimentally produced meningeal sarcomas were classified in the fibrous-(7 cases), the spindle cell-(2cases) and the polymorphic cell-types (2 cases) histologically and histochemically. It seemed that the polymorphic cell sarcoma was the most immature and malignant, on the ground of not only the morpho-logical findings, but intracellular RNA- and DNA-increasing according to Methylgreen-Pyronine stain (Brachet's method). While it was considered about the developmental history of meninges and the classifi-cation of meningioma in many references, especially Globus' concept, it was concluded that the histo-genesis of the produced tumors must be traced back to the primitive meningeal mesenchyme.

The cerebral tissues surrounding the implanted carcinogenic substances were analysed histologically and histochemically, and it was supposed that atyp-ically proliferating cells accompanied with increas-ing of intranuclear DNA and intracytoplasmic RNA in the granulomatous tissue should develop to the meningal sarcoma. Microglial cells and multinuclea-ted giant cells phagocyted M-C pigments and inhib-ited the gliomatous growing certainly.