Objective: To investigate putative associations between oral melanoma size and parameters of histological grade such as mitotic index, nuclear atypia, junctional activity, ulceration, lymphatic invasion and degree of pigmentation.Design: Retrospective case seriesSamples: 59 samples of canine oral melanoma sourced from six diagnostic laboratories within Australia.Procedures: The size of each melanoma was microscopically measured, and each sample was evaluated for parameters of histological grade including mitotic index, nuclear atypia, junctional activity, ulceration, lymphatic invasion and degree of pigmentation, by a veterinary pathologist. The association between tumor size and histological outcomes was then explored using a variety of statistical analyses.Results: A significant relationship was identified between the size of oral melanomas and one histological parameter of grade: lymphatic invasion; with larger tumors, more likely to show invasion (P = 0.023), and further analysis revealed two applicable size thresholds for different clinical scenarios. Lymphatic invasion can confidently be ruled out for tumors <6.5 mm (100% sensitivity), and ruled in for tumors >24.5 mm (100% specificity) in diameter.Conclusions and clinical relevance: The two thresholds developed for lymphatic invasion provide fast, easy and clinically useful recommendations that allow for the early prognostication of oral melanomas based on clinical size.
|Number of pages||6|
|Journal||Journal of the American Veterinary Medical Association|
|Publication status||Published - 15 May 2020|