Light micrograph of a section of human male penile tissue showing penile skin cancer. Penile skin cancer or cancer of the penis is when cells grow out of control on or in a man's penis. It often starts in skin cells and can work its way inside. It's rare, but can be treated if found early on. There are several types of penile cancer, including, squamous cell or epidermoid carcinoma, which is the most likely making up 95% of penile cancer cases. Men who are particularly at risk are those who have been diagnosed with the human papillomavirus (HPV), are aged over 60, smoke, have a weakened immune system because of HIV or AIDS and have not been circumcised.