中村 淳¹, 中村 宏彰¹, 佐藤 建¹, 米満 伸久², 伊山 明宏¹

Jun NAKAMURA¹, Hiroaki NAKAMURA¹, Ken SATO¹, Nobuhisa YONEMITSU², Akihiro IYAMA¹

¹社会医療法人祐愛会織田病院外科, ²佐世保中央病院病理部

¹Department of Surgery, Yuaikai Foundation and Oda Hospital, ²Department of Pathology, Sasebo Chuo Hospital

キーワード : breast, pleomorphic adenoma, intra-cystic tumor

症例は99歳，女性．左乳頭分泌物を主訴に来院し，左乳房A区域の皮膚直下に約1 cm大の有痛性腫瘤を認めた．乳腺超音波検査で嚢胞内腫瘍の形態を呈し，前方境界線の断裂と内部に血流信号を伴っており，嚢胞内癌を疑った．マンモグラフィでは所見を認めなかった．穿刺吸引細胞診で乳管癌疑い（Class Ⅳ）の診断であった．局所麻酔下に乳房部分切除術を施行し，最終病理診断は乳腺多形腺腫であった．また，右乳房には非浸潤性乳管癌が存在したが，生命予後には影響しないと判断し経過観察とした．乳腺多形腺腫は非常にまれな良性腫瘍で，本邦では本症例を含めて20例の報告がある．また，嚢胞内腫瘍の形態を呈した症例は本症例しかなかった．非常にまれな超音波像と考えられたため，文献的考察を加えて報告する．

A 99-year-old woman visited our hospital with a complaint of left nipple discharge, and a tumor was found in the inner-upper quadrant of the left breast. The tumor was 1 cm in diameter and painful, located just below the skin. Ultrasonic examination showed an intra-cystic tumor with an interruption of the interface between adipose tissue and gland, and a blood flow signal at the solid part of the tumor was detected. No findings were found on mammography. As a result of fine-needle aspiration cytology from the left intra-cystic tumor, ductal carcinoma was suspected. Therefore, left partial mastectomy was performed under local anesthesia, and the tumor was pathologically diagnosed as pleomorphic adenoma. Although noninvasive ductal carcinoma was found in the right breast, it was considered that the disease of the right breast was unrelated to her prognosis. Pleomorphic adenoma of the breast is a very rare benign tumor, and only 20 cases including this case have been reported in Japan. Among them, this is the only case that exhibited the morphology of an intra-cystic tumor, which is an extremely rare finding in ultrasonic examination of pleomorphic adenoma of the breast. Here, we review the clinicopathological features of 20 cases of pleomorphic adenoma of the breast.