Cornell veterinarians were astounded when they witnessed the remarkable regeneration of a puppy’s lower left mandible after having to remove most of it due to cancer. While similar occurrences have been observed in children, this marks the inaugural instance documented in dogs, regardless of their age or breed.
The protagonist of this incredible tale is Tyson, a three-month-old French bulldog. Originally slated for cleft palate surgery at Cornell’s Dentistry and Oral Surgery Service in the spring of 2023, Tyson’s medical journey took an unexpected turn when his primary veterinarian discovered a malignant tumor on his jaw.
“Tyson’s tumor was an oral papillary squamous cell carcinoma, which is a malignant cancer in dogs,” said dentistry and oral surgery resident Alexandra Wright, DVM ’18. She led Tyson’s care team. “Oral squamous cell carcinoma is the second-most common malignant oral tumor in dogs, and this papillary subtype has previously been reported in young dogs.”
Wright, along with co-authors Dr. Nadine Fiani, an associate clinical professor and section chief, and Dr. Santiago Peralta, an associate professor in the Dentistry and Oral Surgery Service, published a comprehensive report on the case in Frontiers in Veterinary Science.
In their study, Wright elucidated to Tyson’s owners, Melissa Forsythe and Mike Lacagnina from Rochester, New York, the necessary procedure to address the tumor. They explained that a substantial portion of the puppy’s lower left mandible had to be excised to remove the tumor, resulting in a compromised lower jaw function and altering Tyson’s quality of life.
“We didn’t know if we wanted to put a puppy through all this. The prognosis at the time was uncertain,” Forsythe said, according to the Cornell Chronicle.
However, since Tyson’s CT scans were clear. This meant that the cancer hadn’t spread to other sites in the body, “we decided to give him a chance and continue with surgery. We had no idea his jaw would grow back.”
While there had been sporadic instances of mandible regeneration in young dogs, Tyson’s situation appeared less promising due to the extensive bone removal. However, the case report reveals that Tyson defied expectations, largely owing to the preservation of a substantial amount of periosteum during the surgery. The periosteum, a delicate membrane enveloping bone surfaces, harbors vital blood vessels and nerves essential for the original mandible’s growth. This preservation likely facilitated Tyson’s remarkable recovery, allowing for unexpected regeneration beyond initial estimations.
“This was likely imperative to the regeneration of new bone,” Wright said. It also helped that the dog’s tumor was detected so early, though the precise reason for the jaw regrowth in Tyson’s case remains a history-making mystery.
“More has to be done to understand the likelihood of this occurring in other dogs and if a specific age range makes a difference,” Wright said, “but this case documents a very positive surgical outcome in a life-threatening situation.”
Tyson’s reconstructed mandible, while lacking some typical features like the mandibular canal and teeth, is remarkably functional, nearly matching the original in functionality. Despite being considered abnormal due to these differences, it shares the same length as its counterpart on the right, which effectively prevents misalignment. Furthermore, the absence of cancer in the regenerated bone underscores the success of the procedure.
Following this reconstructive surgery, Tyson proceeded with another operation to correct his cleft palate.
“He spent the majority of his puppyhood wearing an E-collar, not able to play with toys or chew on anything,” said Forsythe, who would take him out for walks around the house just to keep him stimulated. “He was the best patient.”
She continues to avoid giving him solid food or tough toys, but he delights in his moistened kibble and assortment of plush toys.
Forsythe regularly updates Wright on Tyson’s vibrant post-Cornell life. Tyson has recently completed obedience training, aced his Canine Good Citizen test, and even strutted his stuff in a Christmas parade alongside his fellow canine companions. Wright finds this aspect of the case to be the most fulfilling.
Forsythe hopes Tyson’s outcome will benefit other dogs who share the same diagnosis as well. Wright agreed and said, “His case now demonstrates the possibility of complete bone regeneration when working with a patient this young.”
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