Factors that may increase the risk of Wilms' tumor include:

  • Being black. Black children have a slightly higher risk of developing Wilms' tumor than do children of other races. Children of Asian descent appear to have a lower risk than do children of other races.
  • Having a family history of Wilms' tumor. If someone in your child's family has had Wilms' tumor, then your child has an increased risk of developing the disease.

Wilms' tumor occurs more frequently in children with certain abnormalities present at birth, including:

  • Aniridia. In this condition the iris — the colored portion of the eye — forms only partially or not at all.
  • Hemihypertrophy. A condition that occurs when one side of the body is noticeably larger than the other side.
  • Undescended testicles. One or both testicles fail to descend into the scrotum (cryptorchidism).
  • Hypospadias. The urinary (urethral) opening is not at the tip of the penis, but is on the underside.

Wilms' tumor can occur as part of rare syndromes, including:

  • WAGR syndrome. This syndrome includes Wilms' tumor, aniridia, abnormalities of the genitals and urinary system, and mental retardation.
  • Denys-Drash syndrome. This syndrome includes Wilms' tumor, kidney disease and male pseudohermaphroditism, in which a boy is born with testicles but may exhibit female characteristics.
  • Beckwith-Wiedemann syndrome. Signs of this syndrome include abdominal organs that protrude into the base of the umbilical cord, a large tongue (macroglossia) and enlarged internal organs.
Nov. 06, 2014