乳腺線維腫症（Fibromatosis）の超音波所見

Kumi Sato; 佐藤久美; Kumiko Kamitani; 神谷久美子; Nami Ebi; 衣非南美; Kyoko Yoshimura; 吉村京子; Masami Yamashita; 山下雅美; Junko Matsumoto; 松本順子; Mai Izumi; 泉舞; Satoshi Toyoshima; 豊島里志; Minoru Ono; 小野稔; Shoshu Mitsuyama; 光山昌珠

doi:10.11272/jss.305

乳腺線維腫症（Fibromatosis）の超音波所見Ultrasonographic Findings of Mammary Fibromatosis

佐藤久美¹，神谷久美子¹，衣非南美¹，吉村京子¹，山下雅美¹，松本順子¹，泉舞¹，豊島里志²^,*1，小野稔³^,*2，光山昌珠⁴Kumi Sato¹, Kumiko Kamitani¹, Nami Ebi¹, Kyoko Yoshimura¹, Masami Yamashita¹, Junko Matsumoto¹, Mai Izumi¹, Satoshi Toyoshima²^,*1, Minoru Ono³^,*2, Shoshu Mitsuyama⁴

¹ 北九州市立病院機構北九州市立医療センター診療支援部臨床検査技術課Department of Clinical Laboratory, Kitakyushu City Hospital Organization Kitakyushu Municipal Medical Center

² 鹿児島県立大島病院病理診断部Department of Pathology, Kagoshima Prefectural Oshima Hospital

³ 北九州健診診療所Nishinihon Occupational Health Service Center

⁴ 北九州市立病院機構北九州市立医療センター外科Department of Surgery, Kitakyushu City Hospital Organization Kitakyushu Municipal Medical Center

^*1

前　北九州市立医療センター病理診断科

^*2

前　北九州市立医療センター放射線科

受付日：2019年6月28日Received: June 28, 2019

受理日：2020年3月24日Accepted: March 24, 2020

発行日：2020年8月1日Published: August 1, 2020

目的：乳腺線維腫症の超音波検査所見を検討する．

対象と方法：対象は，2000年1月～2018年12月に当院で乳腺線維腫症の病理学的診断が得られた8症例17病変．これらの超音波所見を腫瘤では，形状，境界，境界部高エコー像，内部エコーレベル，内部エコー均質性，後方エコー，構築の乱れ，点状高エコー，血流について評価した．非腫瘤性病変では，乳管の異常，乳腺内低エコー域，構築の乱れ，多発小囊胞，点状高エコー，後方エコー，血流について評価した．

結果と考察：全17病変中，9病変が腫瘤，8病変が非腫瘤性病変であった．腫瘤においては，形状は不整形，境界は不明瞭，内部不均質低エコーを呈し，後方エコーは減弱し，構築の乱れを認めた．境界部高エコー像は1病変のみで認められた．非腫瘤性病変では，8病変すべて境界不明瞭な低エコー域を呈し，構築の乱れを認め，後方エコーも減弱していた．構築の乱れは，17病変中15病変で，太い膠原線維束が周囲の組織を引き込みというよりむしろ押しやっているような組織像を反映し，束がねじれ，渦を巻くような特徴的な超音波所見を呈していた．ドプラ法では，施行された16病変のうち13病変に血流信号を認めたが，豊富な血流ではなく一部に認めるものが多かった．浸潤性乳管癌（硬性型）や浸潤性小葉癌と類似した所見であったが，乳腺線維腫症では境界部高エコー像がみられない病変が多く，病変内に背景乳腺から連続する高エコー域がみられ，ねじれた渦を巻くような構築の乱れが鑑別点になりうると考えられた．若年者に多いことから年齢も鑑別の一助となり，また4症例が異時両側発生，2症例は同時両側に発生しており，患側は勿論，対側乳腺全域の慎重な検査が重要である．

結論：乳腺線維腫症の超音波所見は，後方エコーの減弱と，ねじれた渦を巻く構築の乱れ，病変内に背景乳腺から連続する高エコー域を伴った境界不明瞭な低エコー腫瘤，あるいは低エコー域を呈し，境界部高エコー像がみられないことが特徴と考えられた．

Purpose: To investigate ultrasonographic findings of mammary fibromatosis.

Subjects and Methods: Seventeen lesions (eight patients) histopathologically diagnosed with mammary fibromatosis between January 2000 and December 2018 were examined. For mass lesions, the ultrasonographic findings that were determined are as follows: shape, margin, echogenic halo, internal echo, posterior acoustic features, architectural distortion, echogenic foci, and vascularity. For non-mass abnormalities, the findings that were evaluated are as follows: duct abnormalities, hypoechoic areas in the mammary gland, architectural distortion, multiple small cysts, echogenic foci without a hypoechoic area, posterior acoustic features, and vascularity.

Results and Discussion: Of the 17 lesions, 9 were mass lesions, whereas the other 8 were non-mass lesions. All nine mass lesions had an irregularly shaped and ill-defined hypoechoic mass with posterior acoustic shadowing and whirling architectural distortion. An echogenic halo was detected in only one lesion. All eight non-mass lesions showed an ill-defined hypoechoic area with posterior acoustic shadowing and architectural distortion. Of the 17 architectural distortions, 15 demonstrated twisted and swirling architectural distortion, reflecting the histopathological findings of collagenous fibrous tissues that were thrust into the surrounding breast tissue rather than retracted. Although vascularity was identified in 13 of the 16 lesions in which Doppler sonography was performed, blood flow was not abundant in most cases but rather only partial. These findings were similar to those of scirrhous carcinoma or invasive lobular carcinoma; however, the characteristic ultrasonographic findings of mammary fibromatosis were the absence of an echogenic halo; inclusion of a hyperechoic area that continued into the surrounding breast tissue, reflecting the involved breast tissue; and the accompaniment of a twisted and swirling architectural distortion. Younger age was also helpful for the diagnosis. Because metachronous and synchronous bilateral occurrences were observed in four and two patients, respectively, the contralateral breast should also be examined.

Conclusion: Characteristic ultrasonographic findings of mammary fibromatosis include an ill-defined hypoechoic mass or hypoechoic area with posterior acoustic shadowing, hyperechoic area connected to the surrounding breast tissue, and whirling architectural distortion, without an echogenic halo.

Key words: mammary fibromatosis; ultrasonography

超音波検査技術

研究Research Paper

乳腺線維腫症（Fibromatosis）の超音波所見Ultrasonographic Findings of Mammary Fibromatosis