急性リンパ性白血病の放射線治療後に発生したprimitive neuroectodermal tumorの1例

Primitive Neuroectodermal Tumor Arising 8 Years after Chemotherapy and Radiotherapy for Acute Lymphoblastic Leukemia ： Case Report

Ⅰ．はじめに

　小児の急性リンパ性白血病acute lymphoblastic leukemia（ALL）に対する頭部放射線照射は有効な補助療法の1つで，生存率の改善や再発までの期間を延長してきた⁸⁾．しかし最近になり，小児ALL治療後の長期生存例が増えるに従い，二次性脳腫瘍，特に放射線誘発腫瘍が問題となってきた．われわれは，治療後8年を経過してprimitive neuroectodermal tumor（PNET）を発症した症例を経験したので文献的考察を加え報告する．

We report a case of primitive neuroectodermal tumor (PNET) arising 8 years after chemotherapy and radiotherapy for acute lymphoblastic leukemia.

　A 15-year-old boy with a history of acute lymphoblastic leukemia,at the age of 7,underwent chemotherapy and 14Gy of radiotherapy to the whole brain. He was admitted to our department due to the development of aphasia,right hemiparesis and generalized convulsive seizure. MRI showed an irregularly enhanced mass in the left frontal lobe. A gross total removal of the tumor was performed and histological examination showed it to be PNET. Postoperatively,the patient underwent 20Gy of radiotherapy to the whole brain and 42Gy of local radiotherapy. Follow-up MRI showed no evidence of recurrent tumor 4 months after the radiotherapy.

　This tumor was thought to be a secondary brain tumor arising in this survivor of childhood acute lymphoblastic leukemia and it is a rare complication of successful leukemia treatment.