視機能経過良好な眼窩横紋筋肉腫の1例

A case of rhabdomyosarcoma of the orbit with good visual functions

　4歳女児に発生した眼窩横紋筋肉腫の1例を経験した。患者は眼瞼腫脹に続く眼球突出を主訴に来院し，術前視力は両眼1.2，眼球運動障害による複視を訴えた。CTで眼窩鼻側後方に腫瘍が存在した。Combined lateral and medial orbitotomyを施行し，腫瘍を一塊に摘出した。組織的に横紋筋肉腫の胎児型と診断され，顕微鏡的に摘出断端に腫瘍細胞がみられたためIntergroup RhabdomyosarcomaStudy分類のgroup IIaと考えられ，術後，化学療法，放射線療法を併用した。術後15か月を経過して，視力は両眼とも1.2，眼球運動障害は改善し，複視も消失した。

A 4-year-old girl presented with lid swelling, exophthalmos and restricted eye movement in the left eye. Computed tomography showed a tumor mass posterior nasal to the eyeball. The whole tumor was extracted by combined lateral and medial orbitotomy. The tumor was diagnosed as embryonal type rhabdomyosarcoma. As tumor cells were present at the surgical margin, it was classified as group Ⅱ a according to Intergroup Rhabdomyosarcoma Study. The condition was further treated by chemotherapy and radiation. Fifteen months after surgery, the visual acuity was 1. 2 without restriction of eyeball movement.