多指症を合併した重症の先天性角膜ぶどう腫の1例

Severe congenital corneal staphyloma in a case with polydactyly

要約　背景：多指症は胎生6週頃に起こる先天異常である。目的：角膜ぶどう腫と多指症が併発した新生児の報告。症例：生後4日目の男児が左眼角膜混濁と眼球突出で受診した。妊娠中の経過と分娩は正常で，出生体重は2,864gであった。所見：左眼は突出し，角膜に血管侵入と混濁があった。右手に多指症があった。生後4か月での磁気共鳴画像検査（MRI）で眼内に腫瘤はなかった。左眼の眼球突出が進行し，5か月後にぶどう膜を切除し，眼球内容を除去した。虹彩は角膜後面に癒着し，角膜は肥厚していた。角膜上皮に角化があり，メラニンを含んでいた。Bowman膜，Descemet膜，角膜内皮細胞は欠如していた。結論：本症例に多指症があったことから，左眼の角膜ぶどう腫は胎生5～7週に起こる神経堤細胞の遊走不全による先天性前眼部形成不全（mesenchymal dysgenesis of anterior segment）の重症例と考えられる。

Abstract.　Background：Polydactyly is a congenital malformation that starts at about 6 weeks of gestation. Purpose：To report a case of progressive staphyloma associated with polydactyly. Case：A 4-day-old male infant presented with proptosis and cloudy cornea in his left eye. He was born of uneventful pregnancy with birthweight of 2,864 g. Findings：The left eye showed proptosis and clouded cornea with neovascularization. Polydactyly was present in the right hand. Magnetic resonance imaging（MRI）showed no tumorous lesion in the eye when performed at the age of 4 months. Proptosis progressed further and the left eye was eviscerated at 5 months. The iris was adherent to the posterior surface of the cornea. Corneal epithelium was keratinized and contained melanin granules. The cornea showed no Bowman membrane,Descemet membrane or endothelial cells. Conclusion：Presence of polydactyly suggests that corneal staphyloma in this patient is an instance of severe mesenchymal dysgenesis of anterior segment that develops by disorder of neural crest migration at 5 to 7th week of gestation.