皮膚悪性黒色腫に合併した原田病の1症例

Vogt-Koyanagi-Harada disease in a case of cutaneous malignant melanoma

　原田病にみられる多彩な臨床像は，メラノサイトが何らかの免疫機序により傷害される結果生じると考えられているが，その機序はまだ完全には解明されていない。筆者らは，膝の皮膚に原発した悪性黒色腫の診断に前後して原田病特有の眼所見（夕焼け状眼底，虹彩炎，杉浦のサイン），眼以外の所見（皮膚白斑，白髪，脱毛）および臨床検査所見（髄液細胞増多，HLA-DR4陽性）を認めた1症例を経験した。この症例の悪性黒色腫は表在性拡大型で，自然退縮傾向のある型であった。悪性黒色腫が何らかの誘因となって，メラノーマ細胞と同時に正常なメラノサイトを攻撃する免疫反応が起こり，原田病が発症したことが示唆された。

A 54-year-old woman was diagnosed as malignant melanoma by biopsy of a tumor in the inguinal region. Leukoderma, alopecia and vitiligo had been present since one year before. She was referred to us for possible eye disorders. She had full visual acuity and was free of subjective symptoms. Funduscopy showed generalized depigmentation of the fundus showing sunset fundus. Slitlamp examinations showed mild signs of iritis and disappearance of pigmentation in the perilimbal area (Sugiura's sign). Pleocytosis was present in the cerebrospinal fluid. She was positive for HLA-DR4. We diagnosed her as Vogt-Koyanagi-Harada disease. It appeared that an immune response to melanin-containing tissues, including the uvea, was triggered by malignant melanoma.