Accessory Breast Cancer: A Case Series
Author(s): Nicole Remmert, Nawal Moin, Karla Daniele, Rakhsanda Layeequr Rahman
Accessory breast tissue (ABT) is ectopic breast tissue that occurs due to the failure of the embryonic mammary ridge to resolve during fetal breast development. This can occur anywhere along the milk line, with the axilla being the most common area of occurrence. Due to its pathophysiologic similarity with normal breast tissue, it is also susceptible to developing malignancies . Primary accessory breast cancer accounts for 0.3-0.6% of all breast cancers . The axillary area is the most commonly reported area of accessory breast carcinoma, accounting for 58% of reported ectopic cases . Other reported areas include the parasternal line (18.5%), the subclavicular area (8.6%), the submammary region (8.6%), and the vulvar region (4%) . Given the rarity of primary accessory axillary breast carcinoma, presentation and diagnosis can be challenging. Clinicians ought to be aware of this variance to ensure prompt management. Imaging plays an essential role in diagnosis. Treatment involves a multidisciplinary approach, including surgery, systemic therapy and radiation therapy as dictated by tumor biology and the stage of the disease. Here we report two cases of invasive ductal carcinomas arising in axillary accessory breast tissue.