Immunohistochemical demonstration of Wilms tumour gene product WT1 in a canine "neuroepithelioma" providing evidence for its classification as an extrarenal nephroblastoma.

An intradural extramedullary tumour, surgically removed from the spinal canal of a young dog with paraplegia, had the histological appearance of a nephroblastoma. Subsequent necropsy revealed no evidence of a renal primary tumour or of any other tumour. Similar tumours of the spinal canal have been described previously under a variety of names, in particular neuroepithelioma. With an antibody to the human Wilms tumour (nephroblastoma) gene product WT1, labelling of glomeruloid bodies, similar to glomerular podocytes in human fetal kidney, was demonstrated in the tumour. This finding strengthened the suggestion that it was a nephroblastoma.