Invasive Breast Carcinoma of No Special Type Arising in Supernumerary (Accessory) Axillary Breast Tissue: A Rare Presentation and Diagnostic Challenge

Supernumerary breast tissue is a rare congenital anomaly that typically arises along the "milk line," which extends from the armpit to the groin. Though often benign, supernumerary breasts can be a site for malignancy, including invasive breast carcinoma. This case report describes the diagnosis and management of a patient who developed invasive breast carcinoma in her supernumerary axillary breast tissue, highlighting the importance of early detection and thorough investigation of any breast-related abnormalities, even in accessory tissue.