―症例―悪性胸腺腫の頭蓋内転移例

Malignant Thymoma with Intracranial Metastases

I．はじめに

　胸腺腫は縦隔腫瘍のうち奇形腫や神経原性腫瘍と並んで頻度の高い腫瘍である．また臨床上悪性度の判定が困難である点や重症筋無力症とか赤芽球癆などの特異な合併症を伴う点から，縦隔腫瘍のなかでは特に問題点の多いものといってよいであろう．一般に悪性胸腺腫は局所に浸潤性に増殖する傾向が強く，遠隔転移は少ないといわれている．特に中枢神経系への転移は極めて報告例が少なく，現在までに16例を数えるのみである．われわれは小脳に転移を認めた悪性胸腺腫の症例を経験したので，若干の文献的考察を加え報告する．

　Malignat thymomas usually proliferate invasively and rarely metastasize to other organs. Since the metastases occur predominantly to the liver and kidneys, therehave been only 16 cases with metastatic spreads of malignant thymomas to the central nervous system reported in the literature.

　A 59-year-old man was admitted with complaints of dizziness and vomiting. Three years and three months ago, he had been operated upon for mediastinal tumor, which was diagnosed as a predominantly lymphocytic type thymoma, and then followed by irradiation therapy of 3800 rads. The size of the tumor decreased markedly after the irradiation.