Medullary sponge kidneys and unilateral Wilms tumour in a child with Beckwith-Wiedemann syndrome.

The occurrence of a Wilms tumour in a 4-year-old girl with bilateral medullary sponge kidney. Beckwith-Wiedemann syndrome and congenital hemihypertrophy demonstrates the close relationship between these disorders. Another six cases from the literature with congenital hemihypertrophy and with medullary sponge kidney are discussed, two of them also developed intraabdominal neoplasm.