PHOTOS: 10 Rarest Unbelievable Birthmarks That Challenged Medical Science

Birthmarks are discolored areas on the skin that appear at birth or shortly after birth.

Most birthmarks are not cause for concern. In most cases doctors don’t know why birthmarks appear, and there is nothing that can be done to prevent them.

Here's the list of the most rare birthmarks that challenged medical science:

1. Zhang Hongming from Chongqing, south-eastern China, is nicknamed “Chimpanzee.” He appealed to doctors for help in getting rid of the thick black hair that covers part of his body. The man has a rare birthmark that also covers a large part of his body.

2. Connie Lloyd was born with a benign tumor that grew to cover her nose. She was told that the rare condition could not be cured. However, the shy little girl has a reason to smile at last after surgeons defied the odds and left her with a “nose like mum’s.”

3. This so-called “turtle boy” had a congenital shell-like growth on his entire back. Thanks to a British surgeon, he feels lighter now!

4. George Ashman was born with a bright red blemish on his forehead. After a few surgeries, George is left with a stylish Harry Potter-like scar that looks cool!

5. A six-year-old girl has baffled medics after her skin apparently turned her into “cow hide” girl. The hairy hide has apparently grown until it now spreads over her entire back and is starting to grow on her arms and face.

6. A 16g tragus on an ear birthmark.

7. An Qi, an eight-year-old Chinese boy who has a large birthmark covering one side of his face is going to receive free surgery to remove it.

8. In 2010, a “Holy Cow” Moses was born at a dairy farm in Sterling, Connecticut. Moses was born with a unique “birthmark” that looks like a white cross on its forehead.

9. This puppy was born in Japan with a large, clear, love-heart-shaped pattern in his coat. Shop owner Emiko Sakurada has no plans to sell the puppy, which has been named “Heart-kun.”

10. An unusual cat on a cat’s back.