Definition of Wilms tumor

Wilms tumor: A cancer of the kidney and one of the most important malignancies in childhood, due to loss or inactivation of a tumor suppressor gene called WT1 on chromosome 11. Tumor suppressor genes usually suppress the growth of tumors and control cell growth.

Wilms tumor is usually detected because of an abdominal mass. Other signs and symptoms may include abdominal pain, fever, anemia, hematuria (blood in the urine), and hypertension.

The majority of Wilms tumors are unilateral (in just one kidney) but 5-10% of children have bilateral tumors (in both kidneys) or tumors in one kidney that are multicentric (representing multiple tumors). The average age at diagnosis is 42-47 months for children with unilateral Wilms tumor and 30-33 months for those with bilateral Wilms. But the disease may be diagnosed at any age up to 15 years. Boys and girls are equally at risk.

The treatment of Wilms tumor exemplifies the effectiveness of combining surgery, chemotherapy, and radiation in the treatment of children with cancer. The mortality (death) rate from Wilms tumor was over 60% in the 1950s. However, the survival rate (without recurrence) 2 years after diagnosis now exceeds 90%.

Risk factors for the recurrence of Wilms tumor -- when it recurs, it tends to stay in the locality not far where it started -- include an advanced stage of the tumor (particularly if there is involvement of the lymph nodes near the aorta), an unfavorable microscopic appearance of the tumor, and spillage of tumor cells at the time of surgery.

The name Wilms is neither plural nor possessive. It is the family name of Max Wilms, a German surgeon (1867-1918) who described the tumor. Wilms tumor is also known as nephroblastoma.

Common Misspellings: wilms tumour, wilms tumur