Some male dogs are cryptorchids, a condition in which one or both testicles do not descend into the scrotum. Smaller breeds are prone to developing this condition, but it has been reported in all dog breeds.  The Undescended testicle can be in the abdomen or the inguinal region. If the testicle is in the abdomen, then the operation will be more complex. The only treatment is to have both testicles removed.