Tumors arising from an axillary accessory breast: a 10-year retrospective cohort study at a single center

Pathologic lesions may occur in an axillary accessory breast (AAB). This study aimed to evaluate the characteristics of tumors arising from AABs and to recommend appropriate treatment.

This retrospective study involved 3,544 women (18-65 years old) with AAB at Damsoyu Hospital in Korea from 2014 to 2023. The patients were divided into an AAB with benign tumors (TAAB) group and an AAB without tumors (AAB) group, and the tumors' pathologies were reviewed. A core biopsy was performed on tumors with possible malignancy identified by preoperative ultrasonography. All patients underwent complete excision of accessory mammary gland (AMG) tissue, including tumors. The postoperative results were checked 6 months after surgery.

Fifty-two out of 3,554 patients had tumors confirmed by preoperative ultrasonography. Preoperative core biopsies were performed on 11 patients. Two patients had malignant tumors (invasive ductal carcinoma) identified by core biopsy. Fifty patients had benign tumors identified by postoperative pathological analysis (46 fibroadenomas, 2 fibrocystic changes, and 2 sclerosing adenoses). Carcinoma in situ was confirmed in 2 patients using postoperative pathological analysis. No patients in either group developed tumors in the axilla during the follow-up period. All patients were satisfied with the axillary pain relief and the disappearance of bulging lesions.

We recommend a core biopsy if preoperative ultrasonography indicates a possibly malignant tumor. AAB patients may experience tumors, pain, and bulging appearance of an AMG; thus, complete AMG excision is necessary.