Meningiomaの病理組織学的研究

Histological Studies on the Meningioma

　所謂髄膜腫（Meningioma）（以下Mg．と略す）の病理組織像は極めて複雑多様で，古くから多くの学者により論議せられ，その範疇，発生源，性格，分類，命名法等についてもまだ統一がない。近代におけるMg．の主な病理学的研究はEngert^1）Schmidt^3），　Ribbert^6），　Lissauer^7），　Prym^11），　Ma-llory^15），　Cushing^17），　Dreiffuss^19），　Craig^31），　Pe-nfield^33），　Bailey, Cushing　＆　Eisenhardt^35），　Kre-del^37），　Bostroem^4），　Buckley　＆　Eisenhardt^41），　Guttmann^47），　Hosoi^50），　Bailey　＆　Bucy^51），　Davis　＆　Voris^56），　Laas^65），　Wolf　＆　Cowen^71），　Globus^75），　Cox　＆　Crainage^79），　Cu hing　＆　Eisenhardt 19-38, O．T．　Bailey^95），　Foot^96），　Courville　＆　Abo-tt^99）等であるが　夫々，Mg．の腫瘍細胞を正常組織の細胞に類似を求めて之を発生母細胞と考え，或は髄膜の発生学的な或る段階，又は或る分野に腫瘍の組織像との類似を求めんとし，或は髄膜の発生母組織即ち発生源を三胚葉の何れかに求め，これとMg．との関係を論議せんとした。又一方，髄膜の発生学的研究は，Stone^18），　Landacre^16），　Harrison^24），　Geldern^25），　Harvey　＆　Burr^28），　Flexner^44），　Stone^45），　Harvey, Burr　＆　Campen-haut^53），　Hallerstein^64），　Raven^73）等により行なれ諸説あつて，之がMg．の組織像の複雑性と共に，従来紛糾を来した論議の原因ともなつたのである。

　Mg．　の母細胞として既にBright 1831は蜘網膜細胞を推定し，Golgi 1869は硬膜の内面を掩う細胞を内皮細胞と考えEndotheliomと称し，Sch—midt^3）は硬膜内の腦膜顆粒をその発生源と考え，Ribbert^6）とPrym^11）はMg．　の結合織性格を主張し，又Mallory^15）は彼の所謂meningocyteにfibroglia fibrilsを認めて，これが完全に分化した唯一の腫瘍細胞なりとし，蜘網膜細胞に似るものは未熟，未分化であるとした。即ちその母細胞をarachnoid broblastと称し，Penfield^33）はme—ningeal fibroblastと称した。この細胞は，Fo—ot^96）が指摘するように酸フクシンやMassonのTrichrom染色への反応が通常の線維芽細胞とは異るもので，又Bland　＆　Russel^81）が組織培養においてMg．　は肉芽組織と似てはいるが差異あり，硬膜，軟膜，Mg．　の三者間の近似性は極めて大であることを証していることからもその組織像の示す特殊性と共に，神経系統と関連のあるものとして特異的のものであると推定される。

Because of the fact that there has already been a considerable amount of research done histopathology and tissue culture of so-called meningioma, there are divergent opinions parti-cularly concerning its nomenclature, character, classification and category as well as its origin.

In order to clarify the origin, character and category of meningioma, its histopathological research was performed in 97 cases, consider-ing the embryological, phylogenetical and histo-cultural studies of the meninges which have been heretofore reported by many authors.

Conclusions of the study are as follows:

1) Considering that the neural crest has the character of "mesectoderm (Stone)", the theory of the neural crest origin of the meninges must not mean the so-called neuroepithelial conception, but means that the neural crest itself, as the primordium of the meninges, is of mesenchymal character. Namely, the "mening-eal mesenchyme" derived from the neural crest is to be supposed.

Accordingly, the confusion concerning the origin and character of the meningioma is dissolved.

2) Morphologically, various components ap-pearing in the histological features of the meningioma (meningothelial sheet, bundle and column, meningeal fibroblast and its derivatives, various forms of vascular channels and net-works, various forms of whorls and psammoma bodies, cartilage and osseous tissue, fatt tissue) have close transitional interrelationship each other. Histological features as a whole have a mode of the differentiation of the mesen-chyme.

3) Considering the fact mentioned above from the phylogenetical standpoint of meninges, the histological features of the meningioma must be considered the reappearance of the various stages of the embryological differentia-tion of the meninges. Thus, it has the speci-ficity of a tumor of "meningeal mesenchyme" origin, and all components described above are unitary in this meaning.

The category of meningioma must be extend-ed from these point of view.

4) Various forms of whorls, and psammoma bodies were described and analysed. The whorl formation is one of the most important histo-logical properties of the meningioma as well as vascular component. The whorl, a primitive vascular channel, meningothelial sheet and fibroblastic tisssue have a close histogenetic interrelationship, which is most clearly demonst-rated by various types of perivascular whorl.

5) Histological features of the malignant change of meningioma and sarcomatous mening-ioma were described. Similarity of the mening-ioma and so-called intracranial primary sarcoma was thought, considering the similarity and transition of the histological features and the cytogenetic interrelationship between various kinds of cells appearing in both of them.

Therefore, either of them are supposedly of "meningeal mesenchyme" origin.

6) A few traditional classification of the meningioma was discussed and a new types of classification was introduced by the author.