A retrospective survey on canine intracranial tumors between 2007 and 2017

To clarify the prevalence of canine intracranial tumors in Japan, a retrospective study was performed using data on 186 canine intracranial tumors. Of 186 cases, 159 cases (85.5%) were primary and 27 cases (14.5%) were secondary intracranial tumors. Among primary intracranial tumors, meningioma (50.9%) was the most common, followed by glial tumors (21.4%) and primary intracranial histiocytic sarcoma (12.6%). These 3 tumors were most frequently found in middle-aged to elderly dogs without any sex predilection. Regarding glial tumors, the incidence of oligodendroglial tumors (79.4%) was higher than that of astrocytic tumors (17.6%). A significant breed predisposition (P<0.05) was observed for meningioma in Rough Collie, Golden Retriever, Miniature Schnauzer, and Scottish Terrier; for glial tumors in Bouvier de Flandres, French Bulldog, Newfoundland, Bulldog, and Boxer; for primary intracranial histiocytic sarcoma in Pembroke Welsh Corgi, Siberian Husky, and Miniature Schnauzer. The high incidence of oligodendroglial tumors in dogs and the breed predisposition for primary intracranial histiocytic sarcoma in Pembroke Welsh Corgi have not been reported in previous epidemiological studies on canine tumors. Since the incidence of intracranial tumors was vary among dog breeds, the present results demonstrate the uniqueness of the canine breed population in Japan.