%0 Journal Article
%T Grading Cutaneous Mast Cell Tumors in Cats
%A Giuliano Bettini
%A Silvia Sabattini
%J Veterinary Pathology
%@ 1544-2217
%D 2019
%R 10.1177/0300985818800028
%X Cutaneous mast cell tumors (cMCTs) account for approximately 20% of skin neoplasms in cats. As there is no grading system for these tumors, prognosis is difficult to estimate. Although the typical presentation is a benign tumor that can be cured by surgical excision, a small but important proportion of feline cMCTs is biologically aggressive and can spread to local lymph nodes, precede the onset of disseminated cutaneous disease, or be associated with visceral involvement. A number of macroscopic and histologic features were retrospectively evaluated in cases of feline cMCTs treated with surgical excision with or without medical therapy. Cats were divided into 2 groups based on the clinical outcome. Group 1 included cats alive with no mast cell tumor¨Crelated disease at 1000 days from surgery; group 2 included cats developing histologically confirmed metastatic or cutaneous disseminated disease. The criteria allowing the best differentiation between the groups were used to develop a grading scheme. Groups 1 and 2 were composed by 48 (76%) and 15 (24%) cases, respectively. Tumors were classified as high grade if there were >5 mitotic figures in 10 fields (400¡Á) and at least 2 of the following criteria: tumor diameter >1.5 cm, irregular nuclear shape, and nucleolar prominence/chromatin clusters. According to this scheme, the 15 (24%) high-grade cMCTs had significantly reduced survival time (median, 349 days; 95% CI, 0¨C739 days) as compared with the 48 low-grade tumors (median not reached; P < .001). Further studies are warranted to validate this grading system and test reproducibility on a larger case series
%K cats
%K skin
%K feline
%K neoplasm grading
%K mast cell tumor
%K mastocytoma
%K prognosis
%U https://journals.sagepub.com/doi/full/10.1177/0300985818800028