Wilm’s Tumor can be defined as a rare type of kidney cancer that usually characterizes children often below the age of 5. Also known as Nephroblastoma, this type of childhood cancer can affect one or both kidneys at the same time. The Wilm’s Tumor is named after Dr. Max Wilms, who first discovered it.

The kidneys are a pair of organs found at the back of the abdomen that usually clean the blood by removing excess fluids and waste products, which are then converted into urine. Due to the proliferation of cancer cells, the kidneys stop functioning properly leading to the accumulation of toxins and wastes within the body. Also Read: What You Need to Know About Childhood Cancers


Wilms’ tumors can be categorized into two types:

Favorable Histology

It means that there is no anaplasia. This type of tumor accounts for up to 90 % of Wilm’s tumor and is mostly curable.

Unfavorable Histology

Unfavorable histology usually suggests that the tumors have a nucleus in the cells which is quite large and distorted and is referred to as anaplasia. The more the presence of anaplasia, the harder the tumor is it to cure.
wilm's tumour


Although the exact cause of Wilm’s Tumor is yet undiscovered, it usually happens when there is a mutation in the genetic material that causes the normal kidney cells to grow abnormally and continue to live without dying. This causes abnormal cancer cells to accumulate to form tumorous growths. Thought to come from very specialised cells in the embryo known as a metanephric blastema, these cells are required for the development of the foetal kidney while in the womb. Although in most cases, there is no known connection between parents and children that may lead to cancer, in rare case scenarios, it can be hereditary in nature and transfer from parents to children. Also Read: Kidney Cancer: Causes, Symptoms And Treatment

Risk Factors

The causative factors of Wilm’s Tumor include:

Gender: Wilm’s tumor is common in females than in males.

Race: People from an African-American race have a slightly higher risk of developing Wilms' tumor than the Asian-American counterpart.

Heredity: Children with a family history of kidney cancer are more prone to getting this tumor.

Birth Abnormalities: Children born with certain birth defects or abnormalities like Aniridia (i.e. partially formed iris),  Hemihypertrophy (i.e. one side or part of the body noticeably larger than the other parts), Cryptorchidism (i.e. undescended testicles in boys) and Hypospadias (i.e. when the urinary opening is on the underside of the penis) are at a higher risk of getting this type of cancer.

Rare Health Conditions: Wilms' tumor can occur as part of rare syndromes like Dennis-Drash syndrome (i.e. Wilms' tumor, kidney disease and male pseudo hermaphroditism; a condition where a boy is born with testicles but still show female characteristics), WGAR syndrome (i.e. Wilms' tumor, aniridia, genital and urinary system abnormalities, and intellectual disabilities) and Beckwith-Wiedemann syndrome (i.e. Children born with abnormally large organs). Other syndromes that increase the chance of Wilm’s Tumor include Frasier syndrome, Simpson-Golabi-Behmel syndrome, Perlman syndrome, Bloom syndrome, Sotos syndrome and Li-Fraumeni syndrome.


Although some children don't show up obvious signs of the tumor in the initial stage, common signs and symptoms include:

  • Feeling of an abdominal mass
  • Abdominal pain and swelling
  • Constipation
  • Loss of appetite 
  • Fever
  • Blood in the urine
  • Nausea or vomiting or both
  • High blood pressure
  • Shortness of breath

Diagnosis And Treatment

On noticing any of the above-mentioned signs and symptoms, do consult a doctor right away to get it checked and start the treatment at the earliest. The doctor usually does a thorough physical checkup followed by acknowledging the child’s past medical history and that of the parents to crosscheck the hereditary factor and also perform some diagnostics including:

  • Blood and Urine Tests
  • Imaging tests including Ultrasound, CT-scan or MRI-scan

Staging of Wilm’s Tumor

This is usually done to analyze the spread of the cancer:

Stage I: The cancer is found only in one kidney.

Stage II: In this stage, the cancer has spread to the tissues and structures beyond the affected kidney.

Stage III: The cancer has spread beyond the kidney area to the nearby lymph nodes or other structures within the abdomen.

Stage IV: The cancer in this stage has metastasized outside the kidney to distant structures, such as the lungs, liver, bones or brain.

Stage V: Cancer cells are found in both kidneys as bilateral tumors.


Depending upon the staging of cancer, the doctors decide upon the treatment option which includes: 

  • Surgery
  • Chemotherapy
  • Radiation therapy