Summary

Accessory breast tissue is an uncommon condition which occurs in 0.4–6% of women. It is mostly located in the axilla where it can cause diagnostic difficulty, especially if it is unilateral and large. Usually it is bilateral and presents as an asymptomatic mass during pregnancy or lactation. The diagnosis of ectopic breast tissue is important as it can undergo the same pathological changes that occur in a normal breast, such as mastitis, fibrocystic disease and carcinoma. We present a case of a large right-sided accessory breast in a 32-year-old woman that was clinically diagnosed as pedunculated lipoma. However, subsequent histopathological examination proved it to be an accessory breast tissue with lactational changes.