Oral Pathology in Portuguese Dogs: An Eight-Year Biopsy-Based Retrospective Study

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.