Cancer does not discriminate based on age. We see a large number of patients requiring surgery for oral cancers. Most cancer patients are middle-aged and older pets, but occasionally, we see a patient younger than one year of age. This is a story of a puppy who beat the odds in multiple ways. Presentation Luther, a 22-week-old male German shepherd puppy, was initially presented to our practice on an icy Christmas Eve in 2020, with a large swelling of the rostral mandible that his primary care veterinarian suspected was a cyst due to an unerupted tooth 304. An odontogenic cyst, such as a dentigerous cyst, would be a much more likely diagnosis in a dog this age than what Luther would eventually be diagnosed with. When we did an awake oral examination on Luther, it became apparent that we were dealing with more than just a dentigerous cyst. Luther was young enough to have a mixed dentition: the permanent incisor teeth had erupted, but the canine teeth and some premolar teeth were still deciduous. A soft (but not fluctuant), red, ulcerated mass was approximately 4 cm in diameter, centered in the area of the midline of the rostral mandible, extending beyond the second premolar on the left and to the level of the deciduous canine on the right. Multiple incisor teeth were displaced, and two were either missing or not visible beneath the mass (Figure 1). Figure 1.Large rostral mandibular mass in a 22-week-old German shepherd. Photo courtesy Dr. John R. Lewis Diagnosis An incisional biopsy was performed at that time. Mandibular lymph nodes were also aspirated, and three-view thoracic radiographs were performed and sent to a radiologist for evaluation. Cytology results showed no evidence of metastasis to the mandibular lymph nodes, and the radiologist saw no evidence of thoracic metastasis. Although I was glad to hear of no evidence of metastasis, I was worried that Luther’s tumor was an aggressive one. Fast-forward to one week: I received a diagnosis from the pathologist. Luther’s mass was a Grade 1 osteosarcoma with 15 mitotic figures per 10 high-power fields. I called Luther’s parents, and they reported the mass had doubled in size over the course of the prior week, and they were concerned that if they waited too long, the mass would be inoperable. Surgery We scheduled emergency surgery on New Year’s Eve due to the rapid growth of Luther’s mandibular tumor. I felt bad keeping my colleagues beyond the half day of work we had planned on New Year’s Eve, but we all realized the time-sensitive nature of Luther’s condition and wanted to give him the best chance of beating this cancer diagnosis. The mass seemed to literally be growing by the hour (Figure 2). Figure 2. The mass has enlarged significantly after only one week. Photo courtesy Dr. John R. Lewis We performed a bilateral rostral mandibulectomy, including removal of skin, bone, and teeth to the level of the left mandibular first molar tooth and the right mandibular third premolar tooth (Figure 3A). When performing a bilateral rostral mandibulectomy at this level, the procedure results in two free-floating pieces of the left and right mandible that do not connect in the middle (Figure 3B). Any attempt to suture or wire the remaining mandibles together would result in an abnormal angulation of the mandibles and would likely affect the comfort of the temporomandibular joints. A) The excised tumor with surrounding bone, skin, teeth and soft tissue weighed over half a pound! Clean margins were obtained. B) Cut surfaces of remaining left and right mandibles (arrows). Note the wide gap between the two remaining portions of mandible.Photos courtesy Dr. John R. Lewis Post-surgery After sending the rostral mandible to the pathologist, clean margins were confirmed. We recommended that Luther see a medical oncologist, who would likely recommend chemotherapy. Luther returned to our practice for assessment of healing at two weeks. His mandibulectomy site healed well, with no evidence of dehiscence. Even though he had two independent, free-floating mandibles, he was comfortable and learning to function without the removed portion. He was eating and drinking on his own, albeit sloppily. Here’s the weird part: Two years after the procedure, Luther returned for dental cleaning and assessment of new gingival enlargements around the maxillary canine teeth. We anesthetized him to take a closer look, and upon performing dental radiographs, we were astounded to find the previous free-floating mandibles had somehow fused together due to rostral lengthening of both remaining mandibles and development of what appeared to be a new “symphysis” at the rostral extent of the mandibles (Figure 4). Figure 4.Two years later, an intraoral radiograph reveals growth of both mandibles with formation of a symphysis-like structure near midline. Photo courtesy Dr. John R. Lewis Puppy power This is not the first report of bone regrowth in young patients. Sometimes, when we need to remove a segment of the mandible or a portion of the zygoma due to difficulties opening or closing the mouth, we have reported regrowth of these structures, necessitating additional surgery. A case done at Cornell highlighted a young French bulldog that regrew the entire body of its left mandible after subtotal removal for treatment of a papillary squamous cell carcinoma. Periosteum was preserved ventrally during the French bulldog’s surgery, and it was likely imperative to the subsequent regeneration of the bone.1 However, in Luther’s case, no periosteum was spared in the areas of missing bone due to attempts to obtain margins with an aggressively growing osteosarcoma. Puppies contain many pluripotent stem cells, which likely proved to be very helpful in Luther’s case. Coupled to his young age, in which the mandibles were still in a growing mode, he was able to produce bone to bridge between the two separated mandibular bodies. Oh, to be young and have stem cells again… Four and a half years after surgery, I reached out to Luther’s mom to see how he is doing. “Luther is doing amazing! So far, there’s been no sign of osteosarcoma anywhere else! He’s happy and healthy and just like you told us, has adapted so well to his little jaw!” I’m so thankful to be part of the team that helped extend Luther’s longevity beyond puppyhood! Figure 5.Appearance of Luther 4.5 years after his surgery. Photo courtesy Dr. John R. Lewis John R. Lewis, VMD, DAVDC, Fellow, AVDC OMFS, practices at Veterinary Dentistry Specialists and teaches at Silo Academy Education Center, both in Chadds Ford, Pa. Reference Wright AL, Peralta S, Fiani N. Case report: Spontaneous mandibular body regeneration following unilateral subtotal mandibulectomy in a 3-month-old French bulldog. Front Vet Sci. 2023 Oct 11;10:1281232. doi: 10.3389/fvets.2023.1281232.
