Your eyeball is certainly one place you don't want to grow hair. A young Iranian man knew that since birth, he had a benign tumor on his eye, just below his pupil. But by the time he was 19, the tumor had grown to about a quarter inch thick (0.64 centimeters), and started sprouting hair. The tumor was a limbal dermoid. Although this type of tumor isn't typically cancerous, it can grow cartilage, hair and sometimes even sweat glands. Not everyone with these tumors wants or needs them removed. However, doctors did remove the hairy tumor from the man's eye, according to the case report published in January in the New England Journal of Medicine