Axillary Fibroadenoma: A Rare Ectopic Breast Tissue Anomaly

Accessory breast tissue refers to the presence of breast tissue located outside the typical breast area, usually found along the embryonic milk lines that stretch from the armpit to the groin. We report a 46-year-old female presenting with a painless, progressively enlarging lump in the right axilla for one year. Initially measuring 1 × 1 cm, the swelling grew to approximately 3 × 3 cm. Clinical examination revealed a firm, well-defined, mobile mass, distinct from the right breast, with no skin or nipple changes. Ultrasonography suggested fibroadenoma (BIRADS 2). Histopathological analysis confirmed the diagnosis, revealing a benign encapsulated tumor with biphasic proliferation of bilayered glands and fibromyxoid stroma. This case highlights the rarity and clinical significance of fibroadenomas in axillary accessory breast tissue. Such lesions may pose challenges during diagnosis by mimicking lymphadenopathy or other axillary pathologies