Myeloencephalopathy resembling Alexander's disease in a Scottish terrier dog.

Diffuse degenerative myeloencephalopathy resembling Alexander's disease in a tetraparetic 9-month-old Scottish terrier dog is described. There were widespread deposits of Rosenthal fibers throughout brain and spinal cord in subpial, subependymal, perivascular and white matter regions. A diffuse proliferation of pleomorphic astrocytes in the white matter and subependymal areas was also seen. Demyelination was not a salient feature of the disease.