Stretch marks are white, gray, red or purple fine lines that can form on the breasts as the result of skin distension that happens with pregnancy, weight gain, and sometimes even tumors.

Stretch marks are wavy marks that appear on the skin due to rapid weight gain. Often, they occur during or after pregnancy, commonly appearing on the thighs, abdomen, hips and buttocks. Stretch marks may gradually fade, but can still remain visible.