宇佐見 陽子¹, 角田 博子¹, 梶浦 由香², 河内 伸江¹, 菊池 真理¹, 本田 聡¹, 齋田 幸久¹, 鈴木 高祐³

Yoko USAMI¹, Hiroko TSUNODA¹, Yuka KAJIURA², Nobue KAWAUCHI¹, Mari KIKUCHI¹, Satoshi HONDA¹, Yukihisa SAIDA¹, Koyu SUZUKI³

¹聖路加国際病院放射線科, ²聖路加国際病院乳腺外科, ³聖路加国際病院病理診断科

¹Department of Radiology, ST. Luke’s International Hospital, ²Department of Breast surgery, ST. Luke’s International Hospital, ³Department of Pathology, ST. Luke’s International Hospital

キーワード : breast ultrasound, multiple cystic lesions, breast cancer, mastopathy

目的：乳房超音波において“多発小嚢胞像”は，乳腺内に多数の小嚢胞が局在あるいは区域性に集簇して見られるもの，と定義されている．多くが乳腺症と考えられるが，本邦においてその実態を示した報告はない．多発小嚢胞像の頻度を調べ，その病態・US所見について検討し，多発小嚢胞像の実態を明らかにすることを目的とした．対象と方法：2005年1月‐2009年1月に施行された乳房US（総数6,504例）のうち，チャートレヴューにて多発小嚢胞像を有した30例を対象．悪性の頻度，病理組織学的内訳，US所見，年齢について検証した．結果：多発小嚢胞像を示したのは，6,504例中30例，0.46％．多発小嚢胞像を示した30例中，8例，0.12％が病理組織学的に悪性と診断された（浸潤癌3例，非浸潤性乳管癌5例）．残り22症例は臨床的あるいは病理学的に良性と診断された．US所見を，嚢胞の集簇のみの症例と，集簇する嚢胞の周囲に低エコーを伴う症例とに分類すると，前者は6例，後者は24例であった．悪性8例は全て集簇する嚢胞に合併して低エコーを伴っていた．一方，嚢胞近傍に低エコー域を認めない6例において悪性はなかった．悪性群と良性群の年齢を50歳を境に検討したが，両者に有意差はなかった（P＝0.15）．結論：多発小嚢胞像を示すものの中には頻度は低いものの乳癌も含まれており，単純性嚢胞とは区別して考える必要があることが示された．

Purpose: In breast sonography, “multiple cystic lesions” are defined as numerous cysts existing in clustered formations in segmental or local regions. These lesions are usually caused by mastopathy. In Japan, however, no reports based on these facts have been published. We thus investigated the frequencies, the US findings, the pathology of multiple cystic lesions, and determined their make-up. Subjects and Methods: Thirty cases showing multiple cystic lesions in breast sonographic examinations performed in our hospital (total 6,504 cases) from January 1, 2005 through January 31, 2009 were charted, and we investigated them retrospectively with respect to frequency of malignancies, pathological findings, sonographic findings, and age of patient. Results: The frequency of multiple cystic lesions was 0.46% (30 cases in 6,504 patients). Eight (0.12%) cases were diagnosed as malignancy pathologically (invasive carcinoma, 3 cases; ductal carcinoma in situ, 5 cases). The remaining 22 cases were all diagnosed as benign clinically and/or pathologically. We checked to determine coexistence of low echo and its features. Six cases showed no low echo; 24 cases did. All of the malignant tumors showed low echo; on the other hand, 6 cases showing no low echo were entirely benign. The two groups did not differ in frequency of malignancy. (P=0.15) (group 1: including the group aged of 50 years and above; group 2; subjects under the age of 50). Conclusion: Although low frequencies of multiple cystic lesions were found, these findings included malignant tumors. This points out the importance of distinguishing between multiple cystic lesions and simple cysts.