東野 英利子, 坂東 裕子

Eriko TOHNO, Hiroko BANDO

筑波大学人間総合科学研究科

Comprehensive Human Sciences, University of Tsukuba

キーワード : breast, cancer, ultrasound, halo, triple-negative

乳房超音波画像において乳癌の周囲に幅広い，弱い高エコーを認めた症例を2例報告する．これらの症例では，超音波上，通常のhaloと比較して幅広く，弱いhaloを認めたが，マンモグラフィ，あるいは病理組織学的にいわゆるhaloに相当する癌細胞の脂肪織への浸潤所見は見られなかった．そこでこれら2症例におけるhaloの原因は癌細胞と脂肪細胞の混在という器質的な変化ではなく，リンパ鬱滞による浮腫のような機能的な超音波所見と考えられ，pseudohaloと呼ぶことにした． 2例ともER陰性，PgR陰性，Her2 score0のいわゆるtriple-negative breast cancerであった．一般的にhaloは腫瘍の浸潤部と考えられるが，このように実際には腫瘍細胞の存在しない場合もあり，治療にあたっては注意を要すると考えられる．

Two cases of breast cancer in which wide but weak echogenic areas were seen around hypoechoic masses on ultrasound are herein reported. The findings were different from the usual “halo” on breast ultrasound. A “halo” is almost always specific to breast cancer and is usually caused by cancer infiltration to the surrounding fat. In one case, the tumor was well-circumscribed both on mammography and histologically. In the other case, infiltration of the mass to the surrounding fatty tissue, which corresponds to the ultrasound feature, was not identified on the mammograms. The echogenic areas of these two cases may be functional and were referred to as “pseudohalo.” Both cases were immunologically ER(-), PgR(-), and Her2 score 0, i.e., so-called triple-negative breast cancers.