Rhinencephalic glial cell nests and their possible role in glioma formation: morphometric studies do not reveal significant differences between brachycephalic and dolichocephalic dogs

Gliomas frequently occur in boxer dogs and are often located in the rhinencephalic allocortex. This brain region contains unusual glial cell nests (GCN). The presence of structural abnormalities in the GCN in the boxer dog might indicate that they are involved in the development of gliomas, which would explain the predisposition of this canine breed for glioma formation. Therefore, the brains of six brachycephalic (boxer dogs) and five dolichocephalic dogs were investigated morphometrically. The volumes of the whole brain, the allocortex, and the GCN were estimated following Cavalieri's principle. Unbiased estimates of the numerical density and total number of the two prevailing cell populations within the GCN were obtained using the optical disector method. There was no significant difference for the estimated parameters between brachycephalic and dolichocephalic dogs. The results of the present study did not show any evidence of boxer dog-specific features of the GCN, thus, failing to explain the striking glioma predisposition of boxer dogs.