An eight-month-old, female, mixed-breed dog was presented with bilater
al hind-limb paralysis that reportedly developed over a two-to-three w
eek period and was not associated with trauma. Plain radiographs of th
e spinal column were unremarkable, and a myelogram outlined an intrame
dullary mass of the spinal cord at the first lumbar (L-1) vertebra. A
hemilaminectomy was performed, and a mass that was identified histolog
ically as nephroblastoma was excised from the spinal cord. Following s
urgery, the dog became fully ambulatory and at 22 months postsurgery s
he remains clinically normal. The diagnosis, treatment, progression, h
istogenesis, and pathology of canine nephroblastoma are discussed.