Management of Low-Grade Ductal Carcinoma In Situ in a Supernumerary Breast: A Case Report.

Supernumerary breast tissue arising from incomplete regression of the mammary ridges is rare. This ectopic tissue is affected by the same hormonal influences as a normal breast and can lead to both benign and malignant changes. We describe a case of a female with ductal carcinoma in situ (DCIS) in ectopic breast tissue located below the left inframammary fold. The lesion was surgically excised and treated with adjuvant external beam radiation to the tumor bed. Ectopic breast carcinoma is a rare condition and is often undetected by screening mammography due to its unusual location. Management should involve a multidisciplinary team and adhere to established protocols for breast cancer treatment. We discuss the role of radiotherapy in the treatment of ectopic breast carcinoma.