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 : non-mass lesion, noninvasive ductal carcinoma, DCIS, breast cancer, non-mass abnormalities

非腫瘤性病変は乳腺内の低エコー域，乳管の異常，構築の乱れ，多発小嚢胞，そして点状高エコーを主体とする病変の5つに分類される．非腫瘤性病変として認識される病変で多いのは悪性では非浸潤性乳管癌（DCIS）であり，良性では乳腺症や乳管内乳頭腫などがある．非腫瘤性病変を呈するDCISでは乳腺内の低エコー域が76％と最も多く，次いで乳管の異常が16％であり，この二つだけで全体の90％以上を占める^1）．構築の乱れはDCISでは2％程度であるが，小さな浸潤癌や浸潤性小葉癌などでしばしば認められるので重要な所見である．本稿では5つの分類について解説し，症例も提示する．

Non-mass abnormalities are of five subtypes, i.e., abnormalities of the ducts, hypoechoic areas in the mammary gland, architectural distortion, multiple small cysts, and echogenic foci without a hypoechoic area. The main lesions recognized as non-mass abnormalities include ductal carcinoma in situ (DCIS), fibrocystic change, and intraductal papilloma. In the case of DCIS with a non-mass abnormality, a hypoechoic area in the mammary gland is the most frequent finding at 76%, followed by abnormalities of the ducts at 16%. Architectural distortion is found in about 2% of DCIS; however, it is an important finding because it is often observed in small invasive carcinoma and invasive lobular carcinoma. In this article, we explain the five classifications and present some cases.