Wilms tumor (also called Wilms' tumor or nephroblastoma) is the most common type of kidney cancer that affects children. It is named after Max Wilms, a German doctor who wrote one of the first medical articles about the disease in 1899.

About the Kidneys

The kidneys are 2 curved organs fixed to the back wall of the abdominal cavity. Each kidney is about the size of a fist. One kidney is just to the left and the other just to the right of the backbone. The lower rib cage protects the kidneys.

The kidneys' main job is to filter the blood and rid the body of excess water, salt, and waste products in the form of urine. To do this, a kidney has millions of specialized structures called glomeruli. These structures do the filtering. Each glomerulus is connected to a wavy tube called a nephron that collects and concentrates the filtered fluid, which then becomes urine. Urine leaves the kidneys through long slender tubes called ureters. Each kidney has a single ureter that empties into the bladder where urine is stored until you urinate. Although our kidneys are important, we actually need less than 1 complete kidney to do all of the vital functions discussed above. Tens of thousands of people in the United States are living normal healthy lives with just 1 kidney.

Types of Wilms Tumor

Wilms tumors usually affect only 1 kidney (unilateral). But about 5% of children with Wilms tumor have this cancer in both kidneys (bilateral).

Most Wilms tumors are found only after they have become quite large. They are usually found before they metastasize (spread to other organs). The average weight of a newly found Wilms tumor is about 1 pound – many times larger than the kidney in which it developed.

Even though doctors may think a child has a cancer such as Wilms tumor, they cannot be certain until the pathologist (a doctor who specializes in diagnosis and classification of diseases by lab tests such as examining cells under a microscope) looks at the tumor under the microscope. Wilms tumors are classified into 2 major types depending on how they look under the microscope (also known as histology):

* Wilms tumor with a favorable appearance under the microscope
* Wilms tumor with an unfavorable appearance under the microscope

A tumor has an unfavorable appearance (unfavorable histology) when the nuclei (the central part of the cell that contains the DNA) of the cancer cells are very large and distorted. Also, the cells are not uniform and their appearance varies widely. This is called anaplasia. The more anaplasia that is found, the poorer the chance is for a cure. Favorable appearance (favorable histology) means there is no anaplasia and the chance of cure is very good. About 95% of Wilms tumors have a favorable histology.

My 4 year old was diagnosed with stage 4 wilms tumor in January. You can her site at www.caringbridge.org/jasminedean

She is so beautiful! I will add her to my prayers. I have a friend whose daughter was diagnosed with Wilms Tumor in November. She is in remission now and doing great!

Thank, That is sure an inspiration to know that she is doing good. I hope that Jasmine goes into remssion soon.

Welcome April! I hope you join us and share how she is doing! My 1 year old son was diagnosed at 1month of age with Infantile Fibrosarcoma a rare cancer of the soft tissue that he was born with. He is now in remission and as of June 29th he will be 1 year Cancer free!!!!

My oldest son was diagnosed with Wilm's when he was 29 months old. His was stage IV and favorable histology. His had spread to both lungs and invaded the wall of his inferior vena cava. He will be in remission for 3 years on Sept 22nd. His caringbridge page is www.caringbridge.org/ca/gabreil