A puppy’s jaw spontaneously regrew after Cornell veterinarians removed a majority of his lower left mandible due to cancer. Although this phenomenon has been documented in children, this is the first reported case of its kind for dogs of any age or breed. Tyson, a three-month-old French bulldog, was originally scheduled to see Cornell’s Dentistry and Oral Surgery Service for cleft palate surgery when his primary veterinarian noted a cancerous tumor on his jaw.