123I-IMP SPECTにて特徴的所見を呈した脈絡膜悪性黒色腫の1例

A case of choroidal malignant melanoma with characteristic findings by 123I-IMP single photon emission CT

　50歳男性が5か月前からの左眼視力低下で受診した。6年前に胃癌手術を受けていた。左眼矯正視力は0.7で，後極部に半球形に隆起する黄白色病巣があり，超音波断層検査，磁気共鳴画像検査（MRI）などの所見から転移性脈絡膜腫瘍を疑い，放射線照射を行った。3か月後に左眼矯正視力が0.01に低下した。眼底の隆起性病変はきのこ状に増大していた。¹²³I-IMP single photon emssion CT（SPECT）検査で，造影24時間後にほぼ左眼球全体に及ぶ強い集積があった。この結果，眼球摘出術を行い，病理組織学的に脈絡膜悪性黒色腫であることが判朋した。¹²³I-IMP SPECTが脈絡膜悪性黒色腫の診断に有力であることを示す症例である。

A 50-year-old male presented with blurring in his left eye since 5 months before. He had received gas-trectomy for stomach cancer 6 years before. His corrected visual acuity was 0.7 left. A dome-shaped yellowish-white tumor was present in the posterior fundus. Ultrasonography and magnetic resonance imaging were suggestive of meta-static choroidal tumor. Following radiotherapy, his visual acuity deteriorated to 0.01 3 months later. The dome-shaped tu mor had increased in size to assume mushroom-like appearance. ¹²³I-IMP single photon emission CT (SPECT) showed an intense accumulation in the whole left eye 24 hours after injection. The left eye was enucleated and was di-agnosed with choroidal malignant melanoma. This case illustrates that ¹²³I-IMP SPECT may be useful in the diagnosis of choroidal malignant melanoma.