原発性脳肉腫の2例

PRIMARY SARCOMAS OF THE BRAIN:Report of Two Cases

Ｉ．はじめに

　原発性脳肉腫の頻度はり少なく，全脳腫瘍中1％内外を占めるに過ぎない^1）。Bailey^2）が膠腫と明確にこれを区別し，4型に分類して以来，多数の研究者により報告されるようになり，いろいろな組織学的分類が試みられている。その結果同一組織像でも異なつたり見解が下されていることがしばしばある。特にYuile^3）によつて命名されたいわゆるreticulum cell saromaについては，脳の網内系細胞症とmicrogliaの発生に関連して，興味ある議論が行なわれている。われわれは原発性脳肉腫の2例を経験し，いつくかの組織学的検索を試みたので報告する。

Since Bailey had reoported the primary sarcomas of the brain in 1929, an increasing number of reports have been published elsewhere. Especially, attention was made to the so-called "reticulum cell sarcoma" in relation to the origin of this neoplasm.

Two cases of tumor of this type were reported. Their clinical course were very short when measured from the onset of identifiable clinical manifestations. The tumor tissues occupied the subcortical region of the right occipital lobe and formed irregular invasive masses around the both lateral ventricle in the first case. On the other hand, oval shaped lesion with a diameter of about 5 cm was found in the left cere-bellar hemisphere of the second case, infiltrating to the medulla oblongata and the pons.

Histological examinations revealed that neoplasms of both cases were composed of oval or round cell with a prominent nucleorus, a definite nuclear membrane, and a polygonal nucleus and small amount of cytoplast-ea. Mitotic figures are prominent and numerous phago-cytic cells were also included in the tumor tissues. Perivascular arrangement of these cells with the for-mation of reticulin meshwork were visible by Pap's silver impregnation method. In sections with Cajal's pyrimidine silver method, reactive astrocytosis was demonstrated in the tumor tissues. Penfield's technique for microglia disclosed ameboid granule cells and microglial elements. It is suggested that the tumor of this kind possiblly arises from mesenchymal cells and should he classified melignant lymphoma or primary reticulum cell sarcoma of the brain.