Dysplastic nevus - 異形成母斑
Dysplastic nevi ― 西洋人には生検が推奨されます。
relevance score : -100.0%
References非定型母斑（Dysplastic nevus）またはクラークス母斑としても知られ、皮膚科や皮膚病理学の分野で議論を呼んでいます。見た目が異常で黒色腫の懸念があるため、医師はこれらのほくろを生検することがよくあります。
A dysplastic nevus is also referred to as an atypical or Clarks nevus and has been the topic of much debate in the fields of dermatology and dermatopathology. It is an acquired mole demonstrating a unique clinical and histopathologic appearance that sets it apart from the common nevus. These moles appear atypical clinically, often with a fried-egg appearance, and are commonly biopsied by providers due to the concern for melanoma.
A dysplastic nevus is also referred to as an atypical or Clarks nevus and has been the topic of much debate in the fields of dermatology and dermatopathology. It is an acquired mole demonstrating a unique clinical and histopathologic appearance that sets it apart from the common nevus. These moles appear atypical clinically, often with a fried-egg appearance, and are commonly biopsied by providers due to the concern for melanoma.
非定型母斑またはクラーク母斑としても知られる Dysplastic nevi は、黒色腫を引き起こすことがあります。黒色腫の約 36% は異形成母斑の近くで見つかります。異形成母斑が黒色腫に変化する可能性がある兆候としては、不均一な形状、色素の増加、または灰色がかった色が挙げられます。これらのがんは通常、比較的若い年代（30代半ば頃）に発生し、多発することがあり、体幹部に出現しやすいです。遺伝的には、 dysplastic nevi は良性母斑と黒色腫の中間的な位置づけです。 ただし、黒色腫の 20% ～ 30% が既存の母斑から発生します。 ほとんどの母斑は黒色腫にならないため、予防的に母斑を除去することは通常推奨されません。
Dysplastic nevus, also called atypical or Clark nevus, can be precursor to melanoma, as the observation that 36% of melanomas have dysplastic nevi near the invasive tumor supports. Signs that a dysplastic nevus may have transitioned into a melanoma include asymmetry in contour, a noticeable increase in pigment variations, or a grayish tint indicating regression. These malignancies typically arise at a younger age (mid-thirties), are sometimes multiple, and are often found on the trunk. Molecularly, dysplastic nevi have a profile intermediate between benign nevi and malignant melanoma. While there is a recognized connection between dysplastic nevi and melanoma, it’s crucial to note that only about 20% to 30% of melanomas evolve from preexisting nevi. Given that the majority of dysplastic and typical nevi do not develop into melanoma, preventive removal of melanocytic nevi is not typically advised.
Dysplastic nevus, also called atypical or Clark nevus, can be precursor to melanoma, as the observation that 36% of melanomas have dysplastic nevi near the invasive tumor supports. Signs that a dysplastic nevus may have transitioned into a melanoma include asymmetry in contour, a noticeable increase in pigment variations, or a grayish tint indicating regression. These malignancies typically arise at a younger age (mid-thirties), are sometimes multiple, and are often found on the trunk. Molecularly, dysplastic nevi have a profile intermediate between benign nevi and malignant melanoma. While there is a recognized connection between dysplastic nevi and melanoma, it’s crucial to note that only about 20% to 30% of melanomas evolve from preexisting nevi. Given that the majority of dysplastic and typical nevi do not develop into melanoma, preventive removal of melanocytic nevi is not typically advised.
黒色腫は、皮膚の色素を決定するメラノサイトが癌化したときにできる腫瘍です。メラノサイトは神経堤由来であるため、黒色腫は皮膚だけでなく、胃腸管や脳など、神経堤細胞が分布する他の部位でも発生することがあります。早期黒色腫（ステージ0）の患者の生存率は約97％と高いですが、進行したステージIVと診断された患者の生存率は約10％にまで低下します。
A melanoma is a tumor produced by the malignant transformation of melanocytes. Melanocytes are derived from the neural crest; consequently, melanomas, although they usually occur on the skin, can arise in other locations where neural crest cells migrate, such as the gastrointestinal tract and brain. The five-year relative survival rate for patients with stage 0 melanoma is 97%, compared with about 10% for those with stage IV disease.
A melanoma is a tumor produced by the malignant transformation of melanocytes. Melanocytes are derived from the neural crest; consequently, melanomas, although they usually occur on the skin, can arise in other locations where neural crest cells migrate, such as the gastrointestinal tract and brain. The five-year relative survival rate for patients with stage 0 melanoma is 97%, compared with about 10% for those with stage IV disease.
○ がんのリスク
米国の白人において、異形成母斑がある人は生涯で黒色腫を発症するリスクが10%以上です。一方、異形成母斑を持たない人の黒色腫発症リスクは1%未満です。
○ 異形成母斑のある人に対する予防策
皮膚の自己検査は、黒色腫を予防する（切除可能な非定型母斑を特定する）ため、または既存の腫瘍を早期に発見するために推奨されます。皮膚がんや複数の非定型母斑の個人歴・家族歴がある人は、黒色腫の有無を確認するため、少なくとも年に一度は皮膚科医の診察を受ける必要があります。
【ABCDE】という略語は、医療提供者や一般の方が黒色腫の主な特徴を覚えるのに役立ちます。残念ながら、脂漏性角化症や一部の老人性黒子、さらにはイボでも【ABCDE】の特徴を示すことがあり、黒色腫と区別しにくくなることがあります。
○ [ABCDE]
Asymmetrical：非対称な皮膚病変。
Border：病変の境界が不規則である。
Color：黒色腫には通常、複数の不規則な色が混在します。
Diameter：6 mm を超える母斑は、サイズが小さい母斑に比べて黒色腫である可能性が高くなります。
Evolution：母斑や病変が進行（変化）している場合、悪性化しつつあることを示唆します。