放射線療法が奏効した急性骨髄性白血病視神経浸潤の1例

Radiotherapy was effective in a case of acute myelogenous leukemia with optic nerve involvement

　51歳女子が右眼霧視を主訴として受診した。19か月前に急性骨髄性白血病と診断され，化学療法により完全寛解を得ていた。右眼の視力は0.6で，乳頭浮腫，傍中心暗点，内部イソプタの沈下，CFFの低下があった。髄液検査は正常であった。原因不明の視神経炎として副腎皮質ステロイド薬の内服を開始したが，乳頭浮腫は進行し，9日後に右眼視力は手動弁となった。画像診断で小脳に占拠病変が発見され，臨床的に白血病による視神経浸潤と診断した。抗癌薬の髄注は無効であった。全脳に対する放射線照射を行った。照射5日目に右眼視力は1.0に改善した。

A 51-year-old female presented with blurring vision in her right eye. She had been diagnosed as acute myelocytic leukemia 19 months before. She was in complete remission after chemotherapy. Her visual acuity was 0.6 right and 1.0 left. Funduscopy showed disc swelling in the affected eye. Paracentral scotoma and depression of central isopters were present. Critical flicker fusion frequency (CFF) was decreased. Systemic corticosteroid was started under the tentative diagnosis of idopathic optic neuritis. The visual acuity further deteriorated to hand motion. Computed tomography showed a space-occupying lesion in the cerebellum, sug-gesting that the optic neuropathy was due to infiltration of leukemic cells. Intrathecal chemotherapy was futile. Whole brain radiotherapy induced prompt improvement and the visual acuity recovered to 1.0 five days later.