増殖糖尿病網膜症の硝子体手術後に診断された腫瘍随伴網膜症の1例

A case of paraneoplastic retinopathy diagnosed after vitrectomy for proliferative diabetic retinopathy

要約　目的：糖尿病網膜症に対する硝子体手術後に腫瘍随伴網膜症と診断された1症例の報告。症例：58歳，男性。右眼視力低下を主訴に初診。両眼の硝子体出血を伴う増殖糖尿病網膜症の診断で，両眼に硝子体手術が行われた。術中術後に合併症はなく，検眼鏡的に糖尿病網膜症は沈静化したようにみえたが，手術の1年後に視力低下，網膜電図のa波減弱および求心性視野狭窄が進行した。全身検索で直腸癌が発見され腫瘍随伴網膜症と診断された。結論：高齢者で眼内手術の術後に原因不明の視機能障害が生じた際には，腫瘍随伴網膜症も考え全身検索を行うべきである。

Abstract.　Purpose：To report a case of paraneoplastic retinopathy diagnosed after vitrectomy for proliferative diabetic retinopathy. Case：A 58-year-old male presented with impaired vision in the right eye. He had been diagnosed with diabetic retinopathy one year before. Findings：Corrected visual acuity was counting fingers right and 0.2 left. The right eye showed massive vitreous hemorrhage. The right eye received vitrectomy with intraoperative photocoagulation. Visual acuity improved to 0.5 one month later. The left eye developed vitreous hemorrhage 6 months later and was similarly treated as the fellow eye. Visual acuity decreased gradually along with constriction of visual field in both eyes another 6 months later. Systemic studies led to the detection of colon cancer, leading to the diagnosis of paraneoplastic retinopathy. Conclusion：This case illustrates that paraneoplastic retinopathy may underlie visual impairment of unknown cause following intraoperative surgery.