Polymastia

What is poly​mas​tia?

Polymastia, or accessory breasts, is a rare, congenital (present at birth) condition in which a child is born with an additional breast or breast tissue. The additional breast may or may not have a nipple and areola (ring around the nipple).

Risk factors

Polymastia affects both females and males and usually occurs along the milk line (area of the body that extends from the armpit, down the front of the breast and to the groin). Additional breast tissue can also be found in the back, face or thigh.

What are the signs and symptoms of poly​mas​tia?

The main sign of polymastia is an additional breast or breast tissue. Symptoms affect the additional breast and typically become worse during puberty, menstruation or pregnancy.

Symptoms of poly​mas​tia include:

• Tenderness
• Swelling
• Benign (non-cancerous) or malignant (cancerous) tumors

Rare symptoms of poly​mas​tia include:

• Abscesses (a pus pocket)
• Cysts (fluid or gas pockets)
• Mastitis (infection)

What are the causes of poly​mas​tia?

Polymastia typically occurs in the womb during the development. During normal development, breast tissue will develop along the milk line, and additional tissue will disintegrate and be absorbed into the body.

Polymastia occurs when the additional tissue doesn’t disintegrate before birth. This condition can be inherited and run in families.