Implications of a Supernumerary Nipple Breast Cancer in a BReast CAncer Sequence Variation Carrier: A Case Report

Supernumerary nipples develop on the chest and abdominopelvic regions along the embryonic milk line. Their anatomy varies from isolated accessory nipples to complete supernumerary nipples (accessory nipple, areola, and underlying glandular breast tissue). Patients with a pathogenic BReast CAncer (BRCA) sequence variation are at an increased cumulative risk of developing breast cancer, and it is the standard of care for them to be offered medical or surgical risk reduction. Given the relatively low prevalence of breast cancer within supernumerary nipples and ectopic glandular breast tissue, no current recommendations exist to guide multidisciplinary management of patients with BRCA sequence variations and ectopic breast tissue. Our case is of a 62-year-old female BRCA-1 carrier with a previous history of right breast cancer who developed a new primary breast cancer within a supernumerary nipple after undergoing surgical risk reduction. With no current consensus on the surgical management of supernumerary nipples in BRCA-1 carriers, our recommendation is to perform a thorough physical examination before risk-reducing operation. If supernumerary nipples or ectopic glandular breast tissue are present, wide-local excision of the tissue should be offered for more complete surgical risk reduction.