網膜芽細胞腫の放射線治療後に発生した中頭蓋窩腫瘍の2例

Two Cases of the Middle Fossa Tumor Following Radiotherapy against Retinoblastoma

I．はじめに

　網膜芽細胞腫は二次発癌の多発する疾患のひとつとして知られている．Abramsonら^1）によれば，700例余りの網膜芽細胞腫の患者のなかから90例以上の二次腫瘍が発生し，しかもその大半が放射線照射部位に一致して出現しているという．この事実は網膜芽細胞腫の発癌遺伝子の問題，および放射線による発癌作用の問題の両者と深い関係があり，極めて興味深い．

　今回，われわれは網膜芽細胞腫の放射線照射部位に出現した中頭蓋窩腫瘍を2例経験したので，ここに報告する．なお，症例1は金子ら^6）が既に報告したものと同一例である．

Two cases of brain tumors which developed after radiotherapy against retinoblastomas are reported. A 17-year-old girl was admitted with a chief complaint of swelling in her forehead after head injury in July, 1981. At 7 mouths old her left eye had been enucleated and she had received radiation therapy of 40 Gy to the right eye because of her bilateral retinoblastoma. On admission a CT scan revealed a high density mass with a partial low density area in her right middle fossa. A right frontotemporal craniotomy was performed and the tumor was removed subtotally, which was di-agnosed as a malignant fibrous histiocytoma.