What is a Wilms tumor?

Updated: Mar 04, 2019
  • Author: Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR; Chief Editor: Eugene C Lin, MD  more...
  • Print


Wilms tumor, or nephroblastoma, is the most common solid renal mass and abdominal malignancy of childhood, with a prevalence of 1 case per 10,000 population. [1, 2, 3, 4] Conversely, it is very rare in adults, with an incidence rate of less than 0.2 per million per year. [5, 2, 3, 4] The tumor (see the images below) occurs in both hereditary and sporadic forms, and approximately 6% are bilateral. [6] Most are unicentric and arise from the kidney. Extrarenal Wilms tumors (EWTs) are rare and most commonly found in the retroperitoneal space (44.4%) and the uterus (14.8%). [7]  The results of treatment of Wilms tumor have improved in recent years, reaching 4-year overall survival in the favourable histology group of nearly 90%.

The most common clinical presentation involves an asymptomatic abdominal mass with insidious growth. Secondary hypertension may be observed in as many as 25% of patients as a result of increased renin levels. Initial ultrasonography is commonly performed, and sonograms demonstrate a smooth, well-defined mass of renal origin with uniform echogenicity.

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!