脈絡叢乳頭腫の微細構造

THE ULTRASTRUCTURAL STUDY OF CHOROID PLEXUS PAPILLOMAS

I．はじめに

　脈絡叢乳頭腫（以下CPPと略す）の微細構造は1960年Luseの報告が最初であるがその後Carterら（1972）^3），GhatakおよびMcWhorter （1976）^8），Milhoratら（1976）^16），WolfsonおよびBrown （1977）^22）により研究され，ほとんどの点で正常脈絡叢（以下CPと略す）^5,17）と類似していることが報告されている。われわれは4例のCPPをmouseおよびchickのCPと比較しながら，光顕および電顕にて検索し，CPとCPPの共通点と相違点を明らかにした。共通点の中でも，tightjunction （以下TJと略す）については，これまで一応CPと同様CPPにも存在することが指摘されてきたが^3,8,16），隣接する細胞膜のouter-leafletの癒合は証明されてはいない。この論文でわれわれは，CPPにもCP同様，隣接せる細胞膜のouter-leafletの癒合を有するtight junctionが存在することを明らかにし，さらに，このTJが血液脳脊髄液関門と髄液産生能力に対してもっている意味について考察を加えたい。

Four cases of choroid plexus papilloma (CPP) obtained at the time of surgical excision were examined by light and electron microscopy and compared with normal choroid plexus (CP) of mouse and chick. Ultrastructurally CPPs were the same as CP except in the following two points: In CCPs 1) pinocytotic vesicles of the vascular endothelium and 2) cytoplasmic filaments were more increased in number than in CP.

In one case, which showed malignant changes in some parts, we found prominently increased spot desmosomes and cytoplasmic filaments as compared with other three cases, microcysts at the apical portion with other features suggesting the secretory process except for the absence of basal infoldings and myelin bodies.

As for the apical tight junction fusion of the two outer-leaflets of the adjacent cytoplasmic membrane was observed as in CP. This fact suggests that there is a blood-CSF barrier also in CPPs as in CP.