Wilms Tumor: Meaning, Causes, Symptoms, Treatment (Nephroblastoma)

Written by Medicover Team and Medically Reviewed by Dr Sarita Shrivastva , Oncologists

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Wilms Tumor or nephroblastoma is a rare type of kidney cancer that primarily affects children. It usually develops before the age of 5 and is one of the most common childhood cancers of the kidneys. The condition arises when abnormal cells in the kidney grow and form a tumor.

Many children with Wilms tumour have only one affected kidney but in rare cases, it can develop in both kidneys. The treatment success rate for Wilms tumour is high and many children recover fully with timely diagnosis and proper care because of the medical advancement and technological development.

Different Types of Wilms Tumour

Doctors classify Wilms tumor into two main categories based on how the cancer cells look under a microscope. This classification is very important because it helps analyse how the tumor will behave and how well it may respond to treatment.

Favourable histology'

This is the most common type of Wilms tumor. Under the microscope, the cancer cells appear closer to normal without major abnormalities. Children with this type generally respond very well to treatment and the long-term outlook is excellent in most cases.

Unfavourable histology (Anaplastic Wilms tumour)

In this type, the cells show significant abnormalities such as irregular shapes or rapid and uncontrolled growth. This makes the tumour more aggressive and more challenging to treat. Children with anaplastic Wilms tumor may need more intensive therapy and closer follow-up.

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Wilms Tumor Signs and Symptoms

The signs and symptoms of Wilms tumor can vary from child to child. In the early stages, the tumor may not show any noticeable signs. Symptoms usually develop as the tumor grows larger or spreads beyond the kidney.

• Abdominal lump or swelling: The most common sign. Parents notice a firm, smooth mass in the belly while bathing or dressing their child.
• Some children may complain of pain or fullness in the abdomen.
• Unexplained fever without infection may be an early warning sign.
• Loss of appetite and gradual weight loss are common as the tumor grows.
• Blood in urine or hematuria and the urine may appear pink, red or cloudy.
• Nausea and vomiting.
• High blood pressure or hypertension.

As many children with Wilms tumor look healthy otherwise, parents should never ignore an unusual belly lump or swelling. Early diagnosis and detection are very important for successful treatment and recovery.

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What are the Causes of Wilms Tumor?

The exact cause of Wilms tumor is not completely known but doctors believe it develops from immature kidney cells that fail to grow and function normally during fetal development. Instead of maturing into healthy kidney tissue, these cells continue to divide abnormally and form a tumor.

Several factors can increase the risk of Wilms tumor:

• Genetic Syndromes: Some rare inherited conditions increase the chance of developing Wilms tumor. These include:
• WAGR syndrome: This is a condition that involves Wilms tumor, Aniridia, Genitourinary abnormalities and mental disability or intellectual disability.
• Denys-Drash syndrome: This is a genetic disorder affecting kidney function and sexual development.
• Beckwith-Wiedemann syndrome: This is a growth disorder that causes large body size, enlarged organs and higher cancer risk.
• Family history: In the Majority of cases, tumours occur randomly but having a sibling or parent with Wilms tumor slightly raises the risk.
• Birth defects: Some children born with abnormalities in the urinary tract, eyes or other organs may be more vulnerable to developing Wilms tumour.
• Gene mutations: In rare cases, mutations in specific genes that control kidney development have been linked to Wilms tumour.

It is important to know that in the majority of cases, Wilms tumor is not inherited and happens without any clear reason. Parents should know that nothing they did or did not do during pregnancy causes this condition.

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Wilms Tumor Staging and Progression

Staging is the process doctors use to determine how far Wilms tumor has spread at the time of diagnosis. It is one of the most important steps in planning treatment and understanding prognosis. The stage is usually determined after surgery and imaging tests.

• Stage I:The tumor is confined to a single kidney and can be completely removed by surgery. This is the most favourable stage with an excellent treatment success rate.
• Stage II:The tumor has grown beyond the kidney into nearby cells or blood vessels but can still be surgically removed. Children diagnosed at this stage also have a very high success rate of the treatment.
• Stage III:The tumor cannot be completely removed because it has spread within the abdomen. It may involve nearby lymph nodes, major blood vessels or other tissues. Additional treatments like chemotherapy and radiation are needed.
• Stage IV:The cancer has spread to other organs such as the lungs, liver, bones or brain. Treatment becomes more intensive and the doctor uses several methods like surgery, chemotherapy and radiation to control the disease.
• Stage V:Tumors are found in both kidneys during diagnosis. Special and advanced treatment is needed to remove the cancer cells while preserving as much kidney function as possible.

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What are the Risks or Complications of Wilms Tumor?

If Wilms tumor is not diagnosed and treated on time or if it advances to later stages, it can cause serious health complications. Some complications arise from the tumor itself, while others may be related to treatment.

• Cancer spread or metastasis: The tumor can spread beyond the kidney to vital organs such as the lungs, liver or bones, which makes treatment more complex.
• Kidney damage or failure: If both kidneys are affected or if surgery removes one kidney, long-term kidney function may be reduced. In severe cases, dialysis or a transplant may be required.
• High blood pressure: Kidney tumors can interfere with blood pressure regulation that causing hypertension in children.
• Treatment side effects: Chemotherapy and radiation may cause nausea, fatigue, hair loss, lowered immunity or growth delays.
• Emotional and developmental challenges: Long-time hospital stays, frequent treatments and physical changes can affect a child's emotional well-being, school performance and social development.

When to See a Doctor

Parents should see a doctor if a child shows:

• A lump or swelling in the abdomen.
• Frequent abdominal pain.
• Blood in urine.
• Fever, weight loss or fatigue without explanation.
• High blood pressure in a young child.

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How to Diagnose Wilms Tumor?

Wilms tumor is suspected when a parent or doctor notices a firm swelling or lump in a child's abdomen. Since many childhood conditions can cause similar symptoms, doctors use several steps to make an accurate diagnosis.

• Medical history and physical examination: The doctor begins by reviewing the child's symptoms, medical history and family background. A gentle abdominal exam may reveal swelling or a mass in the kidney area.
• Ultrasound scan: This is the first imaging test used because it is safe and painless. It helps identify the presence of a kidney mass and gives clues about whether one or both kidneys are involved.
• CT scan or MRI: These detailed imaging tests provide more information about the tumor's size, location and whether it has spread to other organs. They are also helpful in planning surgery.
• Blood and urine tests: These tests assess kidney function and check overall health before starting treatment. They also help detect complications such as anemia or infection.
• Biopsy or surgery: In some cases, doctors may remove part or all of the tumor during surgery to confirm the diagnosis. A pathologist then examines the tumor cells under a microscope to determine the type.

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Effective Management and Treatment of Wilms Tumor

Managing Wilms tumor requires a multidisciplinary approach like surgery, chemotherapy, radiation and supportive care. The exact treatment plan depends on the stage, type and pathology of the tumor.

1. Surgery

Surgery is usually the first step in treatment.

• Nephrectomy: Complete removal of the affected kidney along with nearby lymph nodes to prevent cancer spread.
• Partial nephrectomy: Only the tumor and part of the kidney are removed. This is usually done when both kidneys are affected, so healthy kidney tissue can be preserved.

2. Chemotherapy

Chemotherapy uses powerful medicines to kill cancer cells or stop them from multiplying. It may be given:

• Before surgery: To shrink the tumor and make removal easier.
• After surgery: To destroy any remaining cancer cells and reduce the risk of recurrence.

3. Radiation Therapy

In advanced stages, radiation therapy may be recommended. In this procedure, high-energy beams are used to target the tumor area to kill remaining cancer cells. Radiation is used along with chemotherapy for the best results.

4. Supportive Care

Children with Wilms tumor also need care beyond direct cancer treatment.

• Pain relief care like medicines and therapies to keep the child comfortable.
• Antibiotics may be prescribed to prevent infections if the immune system is weakened by chemotherapy.
• Nutritional support like Healthy diet plans to help children regain strength.
• Emotional support such as counselling and play therapy to reduce stress and anxiety.

In nursing practice, the Wilms tumor nursing diagnosis includes:

• Pain management.
• Anxiety reduction for both the child and the family.
• Nausea and vomiting control during chemotherapy.
• Support for normal growth and development.

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Wilms Tumor Prognosis

The outlook for Wilms tumor is generally very positive, especially when the cancer is diagnosed at an early stage and has favourable cell features. Most children recover well and live healthy, active lives.

• Favorable histology: This is the most common form of Wilms tumor. With timely surgery, chemotherapy and follow-up care, more than 90% of children are cured. The long-term survival rate is excellent.
• Unfavourable histology (Anaplastic type): This type is more aggressive and challenging to treat. However, with advanced therapies and close monitoring, many children have a successful recovery.
• Other influencing factors: The final prognosis depends on several aspects like the stage of cancer at diagnosis, the size of the tumor, whether one or both kidneys are affected and the overall health of the child. Children who respond well to initial treatment usually have the best outcomes.

Even after successful treatment, regular follow-up visits are very important. These check-ups help doctors monitor kidney function, detect any possible recurrence early and manage long-term side effects of therapy.

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Conclusion

Wilms tumor is a rare but highly treatable childhood cancer. Most children have an excellent chance of recovery with modern therapies, especially when diagnosed early. Parental awareness of the symptoms, regular check-ups and timely medical care are crucial in improving results.

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