This case is extraordinarily rare, Accessory breast tissue development (polymastia) does not happen often but it can at first glance mimic a very common presentation called a lipoma (adipose tissue tumor). Accessory breasts sometimes do not appear as a normal breast visually, however the cells involved are exactly that, breast tissue. They will act just like normal breast do, growth with puberty, swelling and tenderness during menstruation, and copious milk production post pregnancy. The treatment for these extra breasts is surgical removal of the tissue. I referred her to our plastic surgeon. Thank you so much to my patient for sharing her diagnosis so we can all expand our knowledge. Please be respectful in the comment section. Rare dermatology diagnosis. Dermatology Physician Assistant. Accessory breasts. Polymastia. MrPopZit.