A retrospective analysis of oral tumors in dogs in Switzerland identifies peripheral odontogenic fibroma and melanoma as the predominant tumor types.

Objective: Determine the prevalence, types, and geographical distribution of oral tumors in dogs in Switzerland to provide insights into demographics, tumor characteristics, and trends.

Methods: The medical and pathology records of dogs diagnosed with oral tumors from 2012 to 2022 were sourced from diagnostic laboratories in Switzerland. The focus was on histopathologically confirmed oral neoplasms. Inflammatory, viral, and cystic lesions were excluded. Geographic trends were analyzed by use of postal addresses, revealing local distributions.

Results: Of the 948 reports, 773 cases fulfilled the study's criteria. Benign tumors constituted 63% (487 of 773), with peripheral odontogenic fibroma being the most common (77.8% [379 of 487]). Among the malignant tumors, malignant melanoma was the most frequent (38.1% [109 of 286]), followed by squamous cell carcinoma (21% [60 of 286]) and fibrosarcoma (8% [23 of 286]). The locations of tumors varied, with a higher prevalence of malignant melanoma on the lips. Histopathologic findings indicated ulceration and necrosis were more common in malignant tumors. Significant differences were noted in the mitotic index between benign and malignant groups. No tumor predisposition was noted for any breed. Oral tumors were prevalent in older dogs (median age, 9.4 years).

Conclusions: The findings highlighted the predominance of benign tumors in dogs in Switzerland, with specific histopathologic features distinguishing benign from malignant cases.

Clinical relevance: Understanding the prevalence, types, and geographic distribution of oral tumors based on the representation in dogs in Switzerland may aid in early detection, appropriate diagnostic workup, and informed treatment planning for oral tumors in dogs.