It's most common on the: Keratosis pilaris rubra (KPR) is an inflammatory form of the condition that causes small, grainlike ...

It commonly appears on the arms, thighs, and cheeks ... This viral infection causes small, firm, dome-shaped bumps with a central dimple. It spreads through direct contact or contaminated surfaces.

Some men have little bumps on their scrotum, and they're concerned. What is this? Could it be cancer? First of all, any time you want to know could something be cancer, you need to see a doctor.