Bilateral Ectopic Axillary Breast Tissue in an Adult Female

Abstract

Accessory breast tissue is rare, affecting about 2-6% of the general population and it is usually bilateral. It is a benign lesion that indicates incomplete involution of the milk line during embryogenesis. Most of the defects appear where the embryonic milk-line was located, but cases have been reported of ectopic breast tissue in other parts of the body, including the face, scapula, limbs or buttocks. The first classification of congenital breast anomalies was published by Kajava in 1915, who ordered them in classes from I to VIII. Although this classification was later simplified, the original continues to be that most used. The case is described here of a 42-year-old woman who presented with bilateral axillary lumps which had recently increased in size. Ultrasonography (US) and mammogram suggested ectopic breast tissue and the masses were surgically removed. Histopathological examination of the specimen confirmed the initial diagnosis of ectopic breast tissue. Because of the benign nature of the lesion, no further treatment was needed, but 3 and 6-month and annual follow-up was suggested.