Ectopic breast tissue is estimated to occur in 1% of the population.1 These include accessory mammary glands (polymastia), supernumerary nipples (hyperthelia) along “milk lines” from the axilla to the groin. Embryologic mammary ridges regress during development, excluding the 2 pectoral areas, later forming the breasts. Failure of regression may yield supernumerary breast tissue.2 Some cases have been associated with congenital urologic anomalies3 and familial inheritance.4 Though difficult to accurately characterize, between 0.28% and 0.6% of breast cancers have been reported to occur in ectopic breast tissue away from the milk line,1,5 or “mammae erraticae.” Reported sites include the axillae,6-8 vulva,9 sub-inframammary fold,10 thigh in a male,11 perineum12, buttock, and face.13 Few publications discuss treatment implications. We report our approach to staging, diagnosis, and treatment and review of the literature for accessory breast cancer.