Is the hard bump on my child’s foot a tumor?

Not all hard bumps on your child’s foot are tumors. Some develop under stress, like a pump bump. Others could be the result of a deformity, like a bunion or bunionette. Sometimes hard bumps are related to serious injuries, like a dislocation or broken bone. Other times, however, they are just extra bone tissue that your child is born with. This is the case for something called accessory navicular syndrome. This is a problem with a small, extra bone on the inside of the arch, where the posterior tibial tendon supports the foot.