Abstract
We present and discuss a case report of a 70-year-old patient with a primary carcinoma in accessory breast tissue in the anterior chest wall.
Accessory breast tissue has a reported incidence of 0.3% to 6% in the general population, resulting from an incomplete involution of the mammary milk line. It usually presents as a palpable mass. The most frequent localization of accessory breast tissue and its possible pathologies is the armpit, although it can occur in the inframammary region and rarely on thighs, perineum, groin, or vulva.
The diagnosis is mainly clinical, but imaging findings may be helpful to confirm the suspicion because they are similar to breast cancer within the breast. Ultrasound is the most useful radiological method to evaluate these lesions and guide the suspected diagnosis together with the clinical presentation.
Treatment should be performed under the same principles as breast cancer, both surgical and systemic therapies. The prognosis of accessory breast carcinoma may be poor in cases with delayed diagnosis compared to native breast cancer.