若木 暢々子, 伊藤 吾子, 周山 理紗, 三島 英行

Nonoko WAKAKI, Ako ITOH, Lisa SUYAMA, Hideyuki MISHIMA

日立総合病院乳腺甲状腺外科

Department of Breast and Thyroid Surgery, Hitachi, Ltd., Hitachi General Hospital

キーワード : male breast cancer, gynecomastia, breast ultrasound, color Doppler imaging, elastography

目的：男性乳癌は稀な疾患である．男性最多乳腺疾患である女性化乳房症との鑑別には乳房超音波検査が有用であるが，形態のみでは診断に苦慮することがある．今回Bモードに血流と硬さ評価を加えた超音波所見を後ろ向きに比較検討した．対象と方法：2000年1月から2019年10月に乳房腫瘤や疼痛を主訴に受診し，超音波検査を行い，男性乳癌または老年期女性化乳房症の診断となった92例を対象とした．Bモードにて形態をnodular，dendritic，diffuse glandularの3つに，血流は視覚的に4段階に，硬さはTsukuba elasticity score（スコア）の5段階に分類し比較した．女性化乳房症の形態ごとの特徴について検討した．結果と考察：男性乳癌は6例，女性化乳房症は86例であった．Bモードでは男性乳癌は全例nodularで，女性化乳房症はnodular28例（32.6％），dendritic17例（19.8％），diffuse glandular 41例（47.7％）であった．血流評価は男性乳癌5/6例（83.3％），女性化乳房症21/34例（61.8％）がhypervascularまたはvascularであった（P＝0.399）．硬さ評価では男性乳癌はスコア5が3/5例（60％），女性化乳房症は46/49例（93.9％）がスコア1と2であり，両群間に有意差を認めた（P＜0.005）．血流と硬さ評価のArea Under the Curveは0.7と0.994であった．女性化乳房症のnodular，dendriticは10/15例（66.7％），8/11例（72.7％）がhypervascularまたはvascularであった．Diffuse glandularの35/41例（85.4％）は血流が未評価であった．女性化乳房症の形態ごとで硬さ評価に明らかな特徴差はなかった．結論：男性乳癌と女性化乳房症の鑑別診断には超音波による形態評価に加え，硬さ評価が有用である．

Purpose: Male breast cancer (MBC) is a relatively rare disease. It is important to distinguish it from gynecomastia, which is close in terms of the predominant age and symptoms. The aim of this study was to investigate ultrasound findings with color Doppler imaging and elastography of MBC and gynecomastia. Subjects and Methods: Of male patients with breast symptoms who had undergone ultrasound evaluation between January 2000 and October 2019, the subjects of the study were 92 patients who were diagnosed with MBC or gynecomastia. The morphology was classified into nodular, dendritic, and diffuse glandular; the vascularity on color Doppler imaging was visually classified into four grades; and the elasticity evaluation was divided into five grades using the Tsukuba elasticity score. We compared whether there was a significant difference in color Doppler imaging and elastography between MBC and gynecomastia for each morphology. Results and Discussion: There were six MBCs and 86 gynecomastias. All MBCs appeared as nodular. Gynecomastia was nodular in 28 cases (32.6%), dendritic in 17 cases (19.8%), and diffuse glandular in 41 cases (47.7%). On color Doppler imaging, the evaluation was hypervascular or vascular in 5/6 cases (83.3%) of MBC and 21/34 cases (61.8%) of gynecomastia. There was no significant difference between the two groups (P=0.399). As for elastography evaluation, MBC scored 5 in 3/5 cases (60%). For gynecomastia, 46/49 patients (93.9%) scored 1 and 2, showing a significant difference between the two groups (P＜0.005). Nodular and dendritic gynecomastia was found in 10/15 cases (66.7%), and 8/11 cases (72.7%) had high blood flow, but 35/41 diffuse glandular cases (85.4%) were diagnosed without using vascularity and elastography. The hardness evaluation was not related to morphological characteristics. Conclusion: Combining B-mode ultrasound with elastography is useful for distinguishing MBC from gynecomastia.