Primary lumbosacral Wilms tumour associated with occult spinal dysraphism.

A 4-year-old child presenting with sudden-onset paraplegia and a sacral tumour in association with spina bifida occulta is reported. There were no stigmata of spinal dysraphism at birth. Imaging studies confirmed a sacral tumour with extradural extension up to T10 and spinal dysraphism. The histological features of the extradural and sacral components of the tumour were consistent with a Wilms tumour. The differential diagnosis included a primary sacral teratoma containing Wilms tumour elements or a primary extrarenal Wilms tumour arising in association with a spinal dysraphism. There was no clinical response to chemotherapy or radiotherapy.