五味 直哉

Naoya GOMI

がん研究会有明病院画像診断部

Department of Diagnostic Imaging, the Cancer Institute Hospital of the Japanese Foundation for Cancer Research

キーワード : superficial lymphadenopathy, unknown primary cancer, core needle biopsy, tissue marker

リンパ節転移の診断根拠として，リンパ節の大きさ，短径，形態（リンパ門の脂肪の有無），皮質の肥厚の有無，程度などの組み合わせで検討されている．標準化はされていないが，画像診断は有用でモダリティとして超音波，MRI，CT，PET/CTが用いられる．超音波では乳癌の腋窩リンパ節転移に関しては感度：49‐87％，特異度：56‐97％である．さらに超音波ガイド下針生検を行うと感度79.6％，特異度98.3％，PPV 97.1％と精度が上昇する． リンパ節は癌の原発による所属リンパ節に分類されているが，鼠径，鎖骨上，腋窩リンパ節などリンパ流の要衝のリンパ節では特定の原発巣に関わらず転移がおこり原発不明癌として見つかる場合も多い．これらの表在リンパ節腫大への対応は針生検が有用である．局麻下に低侵襲に生検が可能で，腫瘍性腫大か否か，良悪性，悪性の場合癌／肉腫／リンパ腫の診断，癌の組織型，IHC法によるバイオマーカー検索，遺伝子検査が可能である．表在リンパ節の超音波ガイド下針生検の実際を詳しく解説し，症例（4例）を呈示した．またトピックスとしてリンパ節内への組織マーカー留置を取り上げた．乳癌の腋窩リンパ節転移症例で転移リンパ節内にあらかじめマーカーを留置して治療効果の正確な評価を行っている研究について紹介した．

As a basis for diagnosing lymph node metastasis, combinations of lymph node size, short diameter, morphology (presence or absence of fat in lymph node), presence or absence of cortical thickening, and so on are being investigated. Although not standardized, diagnostic imaging is useful, with ultrasound, MRI, CT, and PET/CT being utilized. Ultrasound has a sensitivity of 49-87% and a specificity of 56-97% for axillary lymph node metastasis of breast cancer. When ultrasound-guided needle biopsy is performed, the sensitivity increases to 79.6%, specificity 98.3%, and PPV 97.1%. Lymph nodes are classified as regional lymph nodes due to the primary cancer, but metastasis occurs at lymph nodes that are important for lymph flow such as inguinal, supraclavian, and axillary lymph nodes, regardless of the specific primary lesion, and is found as a cancer of unknown primary origin. Needle biopsy is useful for dealing with these superficial lymphadenopathies. Biopsy is possible with minimal invasiveness under local anesthesia. If malignant, cancer/sarcoma/lymphoma diagnosis, histological type of cancer, biomarker search by IHC method, and genetic testing are possible. Actual needle biopsy of superficial lymph nodes is explained in detail, and four cases are presented. Implantation of tissue markers in lymph nodes is also discussed. In a case of axillary lymph node metastasis of breast cancer, a study in which a marker was placed in advance in the metastatic lymph node to accurately evaluate the therapeutic effect is described.