Tanaka Yuko, Suzuki Yoshio
Cancer Genome, Dokkyo Medical University Hospital, Mibu, JPN.
Breast Center, Asahi General Hospital, Asahi, JPN.
Cureus. 2025 May 2;17(5):e83340. doi: 10.7759/cureus.83340. eCollection 2025 May.
Accessory breast cancer is a relatively rare condition, and to our knowledge, no previous reports have described synchronous ipsilateral cancers of the breast and the axillary accessory breast. We report a unique case involving a 70-year-old female patient with luminal A subtype breast cancer and triple-negative accessory breast cancer. The axillary tumor, which had become ulcerative and exudative, was diagnosed as an accessory breast cancer with high Programmed Cell Death Ligand 1 (PD-L1) expression. Treatment with immune checkpoint inhibitors targeting PD-L1 was effective. This case highlights the clinical importance of considering accessory breast cancer as a distinct entity and demonstrates the potential utility of immunotherapy in such cases.
副乳腺癌是一种相对罕见的疾病，据我们所知，此前尚无报道描述过乳腺和腋窝副乳腺同时发生同侧癌症的情况。我们报告了一例独特病例，患者为一名70岁女性，患有管腔A型乳腺癌和三阴性副乳腺癌。腋窝处的肿瘤已出现溃疡和渗出，经诊断为程序性细胞死亡配体1（PD-L1）高表达的副乳腺癌。使用针对PD-L1的免疫检查点抑制剂进行治疗有效。该病例突出了将副乳腺癌视为一种独特疾病的临床重要性，并证明了免疫疗法在此类病例中的潜在效用。
