Possible intraspinal metastasis of a canine spinal cord nephroblastoma

A 2-year-old Basset Hound was admitted to the University of Florida Veterin ary Medical Teaching Hospital with progressive spastic paraparesis. At necr opsy, intradural extramedullary tumors produced areas of spinal cord swelli ng and softening in spinal cord segments T11-T12 and L4-L6. Histologic exam ination of the masses revealed sheets of polygonal blastemal cells, epithel ial cells forming tubules and rosettes, and embryonal glomeruloid-like stru ctures in the thoracic mass. Cells in the lumbar mass were less differentia ted, forming rare tubules and no glomeruloid-like structures. The occurrenc e of two tumors in the spinal cord along with the less differentiated appea rance of the lumbar tumor raises the possibility that the lumbar mass arose as a result of intraspinal metastasis. To our knowledge, this is the first report of multifocal or metastatic canine spinal nephroblastoma. In additi on, the vimentin and cytokeratin immunohistochemical staining characteristi cs of these spinal cord nephroblastomas are described.