渡辺 隆紀

Takanori WATANABE

仙台医療センター乳腺外科

Department of Breast Surgery, Sendai Medical Center

キーワード : breast cancer, ultrasound, DCIS, non-mass lesions

非浸潤性乳管癌（ductal carcinoma in situ：DCIS）の超音波画像は，腫瘤から非腫瘤性病変に至るまで大幅なバリエーションが認められる．本稿では，日本乳腺甲状腺超音波医学会（The Japanese Association of Breast and Thyroid Sonology：JABTS）が実施したBC-02研究に基づくDCISの超音波画像の特徴について述べる．BC-02研究では，705例のDCIS症例の超音波画像を画像所見によって分類した．その結果，全病変の60％が非腫瘤性病変，40％が腫瘤であった．各亜分類を見ると，乳腺内の低エコー域が最も多く（全体の50％），次いで充実性腫瘤（31％），混合性腫瘤（9％），乳管の異常（8％）の順であった．これら4つの分類が全体の98％を占めていた．低エコー域を伴わない点状高エコー，構築の乱れおよび小嚢胞集簇は非常に稀であり，全体の約1％であった．DCISの超音波画像は，腫瘤から非腫瘤性病変に至るまで大幅なバリエーションを呈し，乳腺内の低エコー域が最も多く，次いで充実性腫瘤が多かった．

Ultrasound images of ductal carcinoma in situ（DCIS）show a wide range of variations from mass to non-mass lesions. This article describes the characteristics of ultrasound images of DCIS based on the BC-02 study conducted by The Japanese Association of Breast and Thyroid Sonology（JABTS）. In the BC-02 study, ultrasound images of 705 DCIS cases were classified by imaging findings. The results showed that non-mass abnormalities accounted for 60％ of all lesions and masses for 40％. Looking at each subclassification, hypoechoic areas in the mammary gland were the most common（50％ of the total）, followed by solid masses（31％）, mixed masses（9％）, and abnormalities of the ducts（8％）. These four classifications accounted for 98％ of the total. Echogenic foci without a hypoechoic area, architectural distortion, and clustered microcysts were very rare, accounting for about 1％ of the total. The ultrasound images of DCIS were characterized by a wide range of variations from masses to non-masses abnormalities, with hypoechoic areas in the mammary gland being the most common, followed by solid masses.