稀なmalignant thymomaの頭蓋内転移

CEREBRAL METASTASES FROM MALIGNANT THYMOMA

　抄録　Malignant thymomaの脳内転移は，世界で14例の報告を見るにすぎない。今回我々は，malig-nant thymomaの術後6カ月で右片麻痺とGerstmann症候群で発症した転移性脳腫瘍に対して腫瘍摘出後放射線療法を行ない腫瘍の消失を認めた症例を経験した。症例は，56歳男性。昭和59年6月頃より右上下肢脱力感と書字の乱れが出現，その後，頭痛，悪心，嘔吐，右片麻痺，発語障害が出現した。入院後単純CTにて左後頭頭頂部に低吸収域の腫瘍を認め，辺縁には高吸収の壁在結節を認めた。また周囲は造影CTにて増強された。左内頸動脈撮影にて角回動脈末梢部に異常血管像と左後頭頭頂部に無血管野の辺縁に腫瘍濃染を認めた。以上よりmalignant thymomaの脳内転移と診断し腫瘍摘出手術を施行。術直後より右片麻痺の改善とGerstmann症候群の軽快を認めた。また，同部に総線量5590radの照射を行ない，CT上腫瘍の消失を認め，脳血管撮影上でも異常血管像の消失を認めた。以上，術後放射線併用療法が極めて著効を示したmalignant thymomaの脳内転移についてこれを報告する。

Thymoma with extrathoracic metastasis is very rare, especially to the central nervous system. As far as we know, this is the 15 th reported case of cerebral metastasis from malignant thy-moma. The prognosis is very poor and almost all of them die in one to one and half years. We have experienced such a case, who is 56 years old man, presenting Gerstmann's syndrome and right-hemi-paresis 8 months later after thoracotomy for re-moval of thymoma.

At the admission time in this hospital, CT find-ings proved the tumor in the left temporoparietal area, left ventricle deformity and slight midline shift to right side. The average of CT density in the low density area was 20. Peripheral region of the tumor was enhanced by contrast CT. Left carotid angiography showed the ACA shift to the right side and abnormal vascularity of peripheral branches of angular artery (arterial phase) and also tumor stain in late artery (arterial phase) and also tumor stain in late arterial phase. Brain cin-tigram revealed accumlation in the left parietal region. The rt-hemiparesis was rapidly going to be rt-hemiplegia. Therefore, we have performed needle puncture to prevent rt-hemiplegia at the first time. In the course of needle puncture, 90 ml of dark and red fluid was gained at 3. 0 cm depth from the cerebral surface. Immediately, the above two symptomes have improved remarkably. Post operative CT showed the reduction of tumor and improvement of the midline shift. The radical operation have been done 2 days after the needle puncture. The tumor was elastic-soft and hemor-rhagic and appeared dark-red. Histologically, the tumor was the epithelial type of thymoma, which was derived from the mediastinal malignant thy-moma. At 3 rd post operative week, radiation the-rapy was started and reached up to total 5590 rad. So that, we have found that the tumor was vani-shing on the repeated CT examinations. The left carotid angiopraphy revealed no evidence of mid-line shift and vascular abnormality. After 5590 rad, the tumor has almost disappeared.

Now he has no pathological sign and follow up in our outpatient department for 5 months. And we report this case reffering to literatures.