Central neurocytomaの病理組織学的研究—そのhistogenesisに関する考察

Histogenesis of Central Neurocytoma:an immunohistochemical and electronmicroscopic study of four cases

I．はじめに

　1982年Hassoun^3）が提唱したcentral neurocytoma（以下CNと略す）の概念は，その後の症例報告の積み重ねにより，改訂されたWHOの脳腫瘍分類^6）に新しい腫瘍概念として登録されるに至った．CNはその中ではneuronal and neuronal-glial tumorsの項目に記され，neuronal differentiationを強調する説明文が記されているが，そこに“Co-expression of GFAP has been ob—served．”という印象的な一節を見ることができる．ではCNは純粋なneuronal tumorではないのか．われわれは最近4例のCNを経験したので，その光顕，電顕像，及び免疫組織化学像を検討，特にCN組織におけるglial componentの存在に注目，未だcontroversialなCNの発生母地について考察を加えた．

Four intraventricular central neurocytomas were stu-died histopathologically and intriguing findings were obtained with regard to the histogenesis of this tumor. The cases included 3 males and 1 female aged 17-25. The tumors had developed in the regions from the lateral to the third ventricles and were surgically re-moved in all the cases.

A honeycomb appearance was recognized on H & E staining, and the calcification and latticed vascular find-ings closely mimicked the appearance of oligodendro-glioma. A characteristic wide eosinophilic fibrous stro-ma was observed frequently. Immunohistochemically, all four cases were NSE-positive and strongly synaptophysin-positive, and by electronmicroscopy, neurosecretory granules and micro-tubules were observed in all cases and typical synapse structures in 2 cases. GFAP immunoreactivity and glial differentiation, including ependymal cells were exhi-bited electronmicroscopically, such as glial fibrils, basal bodies, centrioles and 9+1 patterned cilia-like struc-tures in 2 cases.

These findings suggest that central neurocytoma is an embryonal tumor in the wide sense, originating from the germinal matrix cell of the lateral ventricles and possessing multipotency, with potent differentiation from mature neurons.