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Treatment for oral tumors in dogs may involve aggressive surgery, radiation therapy, and/or chemotherapy. It is of utmost importance that veterinarians can document the good quality of life (QoL) for patients during and after cancer treatment. In this retrospective study, medical records from 2 private practices during a 10-year period (2011-2020) were searched to identify dogs with confirmed histopathological diagnosis of an oral tumor. Owners of dogs who underwent surgery received a questionnaire to assess their perception of QoL before and after surgery, clinical signs from the oral tumor, pain before and after surgery, physical appearance, and drinking and eating ability after surgery. Forty-two of 45 (93%) owners answered the questionnaire. Thirty-eight owners (90%) perceived that their dog had not changed its appearance after surgery after the hair had regrown. Thirty owners (71%) reported that their dog prehended food and water normally within 4 weeks after surgery. Forty owners (95%) perceived that their dog had more "good'' than ''bad'' days after surgery. Thirty-eight owners (90%) would choose the same treatment again. Our results strongly support that dog owners perceived that their dogs had good QoL after partial mandibulectomy or maxillectomy., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

This retrospective study reported the clinical presentation, histopathologic findings, treatment, results of clinical staging, necropsy findings, and survival times for 20 cats with oral melanoma. The median survival time was 102 days, with a one-year survival rate of 15% ( n  = 3). Metastatic disease was documented in 5 cases. Cats with metastatic disease, tumors within the oral cavity (in contrast to labial tumors), and those treated only palliatively after diagnosis had shorter survival times. One case was monitored from the time of presentation until euthanasia., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Mouth-related neoplastic and non-neoplastic lesions are commonly found in dogs and cats, and their diagnosis and classification are important for treatment planning and prognosis. This retrospective study analyzed mouth-related lesions in dogs and cats between 2000-2019 from the animal pathology laboratory of the Universidad de Antioquia, Medellín, Colombia. A total of 640 mouth-related lesions affecting 572 dogs (89.4%) and 68 cats (10.6%) were reviewed. Lesions were classified as neoplastic or non-neoplastic. The average age for neoplastic lesions was 8.6 years in dogs and 6.4 years in cats, while for non-neoplastic lesions the average age was 7.7 years for dogs and 5 years for cats. Data was analyzed using descriptive statistical methods according to year and source of report, demographic information for the animal, location of the lesion, and diagnosis. Tissue origin and behavior were variables considered for neoplastic lesions. Melanoma was the most common neoplasia in dogs and squamous cell carcinoma was most common in cats. The most frequent non-neoplastic lesion in dogs was gingival hyperplasia, while in cats the inflammatory lesions showed a wide range of morphological diagnoses. This study described many pathological lesions affecting the oral cavity for both dogs and cats and provides useful epidemiological data for both pathologists and clinicians.

The oral cavity of the dog can be the site of several types of pathology including both benign and malignant lesions. The aim of this study was to analyze the frequency and clinical-pathological characteristics of oral lesions present in a cohort of Portuguese dogs. A retrospective observational cross-sectional study on 704 canine oral lesions submitted for histopathological diagnosis to a Veterinary Pathology Center in the north of Portugal from 2010 to 2017 was performed. Gender, age, location of the lesion and the histopathological diagnosis was analysed. From the 704 cases included, 307 (43.6%) were females and 397 (56.4%) males. The mean age was 9.53 ± 3.6 years-old (range 3 to 240 months). The site most frequently affected was the gingiva (n = 283; 40.2%). 342 (48.6%) cases were malignant neoplasms, most represented by oral melanoma (n = 129; 37.7%). 256 (36.4%) cases were benign neoplasms, most represented by fibromatous epulis of periodontal ligament origin/peripheral odontogenic fibroma (FEPLO/POF) (n = 208;81.3%). 106 (15%) were non-neoplastic lesions, most represented by gingival hyperplasia (n = 25, 23.6%). This study provides useful information about frequency and distribution of oral lesions in dogs over a period of eight years allowing valuable comparison with other countries and other species. The most common benign tumours were FEPLO/POF while oral melanoma was the most common malignant tumour.

The majority of the melanocytic neoplasms are considered malignant and highly metastatic. However, a subset of the melanocytic tumors has a more favorable prognosis and the identification of precise prognostic markers for this neoplasm may be useful to guide treatment. The collagen architecture and density have been shown to correlate with tumor progression in human breast cancer and canine mast cell tumors. The purpose of the present study was to investigate the prognostic value of the intratumoral collagen index (ICI) as an indicator of postsurgical survival and its relation with other prognostic markers for canine oral melanomas (OMs). Twenty-two cases were tested for intratumoral collagen density using Masson's trichrome stain and morphometry. No differences were found between dogs regarding survival. The ICI was not correlated with proliferative activity or nuclear atypia. The results presented herein indicate that the quantity of intratumoral collagen in canine OMs is not an efficient indicator of postsurgical survival. Complementary studies about the expression and activity of enzymes that are capable of degrading extracellular matrix (ECM) components are necessary.

A 19-year-old male castrated llama presented with a 3-year history of tooth root abscesses and an osseous mass on the left mandible. Surgical excision of the affected teeth and mass was performed, and histopathologic review indicated that the mass was an oral squamous cell carcinoma. The patient was admitted to the hospital again 4 months later in severe respiratory distress with submandibular edema, and bicavitary effusion. Necropsy results revealed regional and distant metastatic squamous cell carcinoma.

The Iberian lynx is an endangered felid that has been subject to an intensive, ongoing conservation program to save it from extinction. Identification of dental pathologies could play an important role in the survival of this endangered species. The prevalence of periodontal bone loss, tooth resorption, and oral neoplasia was evaluated in this species. Skulls of 88 adult specimens of the Iberian lynx ( Lynx pardinus) from the Doñana Biological Station (EBD-CSIC), Seville, Spain, were examined macroscopically and full-mouth dental radiographs of all specimens were performed. Different stages of periodontal disease were identified in 81.3% of teeth. Approximately two-thirds (64.8%) of the specimens examined had at least 1 tooth affected by stage 3 or 4 periodontal disease. Maxillary and mandibular incisor teeth accounted for a majority (59.4%) of teeth affected by stage 3 or 4 periodontal disease. Tooth resorption affected 12 teeth (0.63% of evaluated teeth) in 6 skull specimens (6.8% of skulls evaluated). Five of the teeth with resorptive lesions were detected on 1 skull specimen. Six teeth (50%) of those affected by tooth resorption were incisor teeth. Only 1 (1.1%) adult specimen showed signs of oral neoplasia. Our study concluded that there is a high prevalence of periodontal disease that could lead to impaired hunting ability, as well as may represent a threat to overall health and subsequent survival of this endangered species. The extremely low prevalence of tooth resorption in L pardinus could open new pathways in the discovery on the pathogenesis of tooth resorption in felids.

This case report describes a rare case of a persistent canine papillomavirus type 1 (CPV-1)-induced oral papilloma that underwent malignant transformation into an oral squamous cell carcinoma (OSCC) in a 3-year-old Labrador retriever cross. Initially, the patient had multiple and multifocal verrucous lesions populating the oral cavity exclusively. The papillomas persisted despite multiple surgical ablations, azithromycin, interferon α-2b, alternative medicines, and off-label drug use of an immunostimulant. After 1 year and 6 months, an aggressive lesion developed at the level of the left mandibular first molar (309) and progressed to a well-differentiated invasive OSCC. The presence of CPV-1 DNA in the OSCC, and the known oncogenic abilities of CPV-1, suggests that this virus might have played a significant role in the emergence of the OSCC that ultimately led to the patient's euthanasia due to poor quality of life. This is the first well-documented case where OSCC has developed from an oral papilloma caused by CPV-1 in which the presence of coinfection by another papillomavirus was excluded by multiple polymerase chain reaction tests using various primers.

Grade and labeling indices for immunohistochemical tumor proliferation markers Ki-67 and proliferating cell nuclear antigen (PCNA) were evaluated in 36 cases of canine oral squamous cell carcinoma (OSCC) based upon intraoral location. Grade was significantly associated with location ( P = .035). Grade II tumors were most frequently diagnosed. Grade I tumors were identified in the gingiva and the buccal mucosa, and grade III tumors were seen in the gingiva and the tonsillar region. Animals with tumors arising from the tonsils and of the tongue tended to be older ( P = .007), and those in the former group were more likely to have metastatic disease at the time of diagnosis ( P = .001). Mean expression of PCNA and Ki-67 proliferation index (PI) for all tumors were 62.54% and 50.70%, respectively, and there was a statistical significant association between the 2 variables ( R = .70; P < .001). Proliferation index was not associated with any of the intraoral locations evaluated, but higher PCNA PI was significantly associated with grade ( P = .031). Ki-67 PI was significantly associated with lymph node metastasis at the time of diagnosis, especially for OSCC of gingival location ( P = .028). The results obtained in this study are preliminary but clinically relevant, since they provide information that can explain differences in biologic behavior among intraoral locations and contribute to more accurate tumor staging to support the choice for different treatment strategies available for OSCC.

An inflammatory gingival mass surrounding resorbing teeth was diagnosed via biopsy in a 9-year-old domestic shorthair cat. A dorsal rim excision was performed to remove the entire mass with associated teeth and bone. Histopathological diagnosis of the en bloc tissue revealed an odontogenic fibromyxoma. Extensive literature review revealed few case reports of companion animals with this neoplasm, and none in a feline patient. This report documents the clinical presentation, diagnostic differentials, surgical therapy, and long-term follow-up of an odontogenic fibromyxoma in a cat.

Oral malignant melanomas are one of the most common oral malignant neoplasms in dogs but are rare in other domesticated species. This case report describes the clinical manifestations and histological appearance of oral melanoma in a ferret ( Mustela putorius furo). To the authors' knowledge, this is the first published description of a clinical case and histopathological findings of oral melanoma in this species.

Squamous cell carcinoma (SCC) is the most commonly encountered malignant oral tumor in cats. The etiology of this locally invasive tumor is likely multifactorial. Several risk factors have been identified, including the use of flea collars, and a history of feeding canned food and canned tuna. Clinical signs vary depending on tumor location. The tumor commonly arises from the gingiva and mucosa of the maxilla, mandible, tongue, sublingual area, or tonsillar region. Maxillary SCC commonly presents clinically as an ulcerative lesion, whereas mandibular SCC is commonly proliferative, expansile, and firm. Lingual/sublingual SCC may be ulcerative, necrotic, infiltrative, or proliferative. In general, feline oral SCC is an invasive and malignant neoplasm regardless of its location. Surgery, radiation therapy, chemotherapy and combinations thereof have been attempted with rarely a satisfactory response. Currently, cures are obtained only in a small subset of cats whose tumors are amenable to complete resection, or where resection with microscopic residual disease is followed by definitive radiation therapy. A multimodal treatment approach likely offers the best chance of success. For cats with advanced disease, palliative care may improve patients' quality of life, albeit transiently. Sequelae associated with tumor progression and local tissue destruction often result in euthanasia of feline patients with oral SCC.

Medical records of patients with a histopathological diagnosis of oral osteoma were reviewed for information on signalment, body weight, history, clinical signs, physical examination and diagnostic imaging findings, surgical procedure performed, and histopathologic characteristics. Clinical signs related to the mass were noted in 2 dogs. One mass was documented to have been present for > 3-years, 3 of the masses were noted on physical examination, and 2 masses were noted during professional scaling and survey intraoral radiographs. All six masses had radiographic signs of bone proliferation without bone lysis. One case had radiographic root resorption of adjacent dentition. Four of the masses were classified as central osteoma and 2 were classified as peripheral osteoma based on clinical and radiographic findings. Four masses were treated with excisional biopsy that consisted of wide excision (rostral maxillectomy) [n = 1] and 3 had marginal excisions (en bloc resection) [n = 3]. Two of the masses were debulked with subsequent biopsy. There was no indication of recurrence in the cases with excisional biopsy and minimal progression in the cases that had lesions debulked > 5.5-months following surgery.

This study assessed proof-of-concept for use of polyamine inhibitor 2-diluoromethylornithine (DFMO) as a treatment for oral squamous cell carcinoma (SCC) in client-owned cats. Polyamine levels in tumor tissue and normal oral mucosa were quantified before and after treatment. DFMO was administered orally to 14 client-owned cats with histologically confirmed oral SCC. Patients were monitored for gastrointestinal, dermatologic, auditory, hematological, and biochemical abnormalities. Total polyamine levels in tumor tissue decreased after treatment, as did the specific polyamine putrescine in both tumor tissue and normal mucosa. Ototoxicity was observed in 5 of 6 cats receiving pre- and post-treatment brainstem auditory evoked potential tests. Subclinical thrombocytopenia was observed in 6 of 14 cats. One cat showed mild post-anesthetic tremors that resolved without treatment. Oral administration of DFMO at doses used in this study resulted in significantly decreased tumor polyamine levels without life-threatening clinical or hematological toxicities. Further studies are warranted to explore pathophysiology of polyamine biochemistry and use of polyamine inhibitors in treatment of cats with oral SCC.

Medical records of dogs diagnosed with oral papillary squamous cell carcinoma between December 2008 and April 2011 were reviewed. Information abstracted included signalment, tumor location, tumor size, computed tomographic (CT) features, evidence of metastatic disease based on cytologic examination of lymph node aspirates and thoracic radiography, treatment, surgical margins, histologic features, and treatment outcome. Dogs included in the study were all sexually altered, predominantly large breed dogs with a mean age of 3.9-years (range, 0.5 to 9.0-years). The most common location was the rostral maxilla. Invasion of underlying bone and lymphadenopathy were evident on CT imaging in most dogs. No evidence of metastasis was found on mandibular lymph node cytology and thoracic radiography. Histologic analysis revealed similar morphologic findings for all surgically resected tumors. Surgical excision with 1-2 cm margins was complete in all cases, with a mean tumor-free interval of 12.1-months.

Oral extramedullary plasmacytomas (EMP) are locally aggressive tumors in the dog that rarely metastasize. They represent 5.2% of all canine oral tumors and 22.0 to 28.0% of all EMPs diagnosed are in the oral cavity. EMPs consist of neoplastic plasma cells that do not arise from the bone marrow. No relationship between EMP and the development of multiple myeloma has been determined in dogs. Complete surgical excision is the primary treatment for this neoplasm and is usually curative. Multiple oral EMPs within the same patient have been rarely reported with tumors arising in the same location in the mouth. To the authors' knowledge, multicentric oral EMP, as described in the following cases, has not been reported in the dog.

Acquired myasthenia gravis is a common neuromuscular disorder resulting from autoantibody directed against the post-synaptic acetylcholine nicotinic receptors in skeletal muscle. Myasthenia gravis has been reported previously as a paraneoplastic syndrome. This case report presents myasthenia gravis secondary to an oral sarcoma in a juvenile Mastiffdog.