Wilms’ Tumor (Nephroblastoma) – Causes, Symptoms & Treatment

Wilms-Tumor (Nephroblastom)

Wilms tumor (nephroblastoma) is the most common tumor disease of children’s kidneys, which affects girls more often than boys. If diagnosed and treated early, a Wilms tumor can usually be cured in the long term.

What is a Wilms tumor?

A malignant (malignant) tumor of the kidney is referred to as a Wilms tumor or nephroblastoma , which primarily affects children, especially those between the ages of 1 and 4 years.

A Wilms’ tumor usually occurs on one side and tends to early metastasize (formation of daughter tumors), which often occurs hematogenously (through the blood) in the lungs, brain, liver and regional lymph nodes. In some cases, a Wilms’ tumor is also associated with congenital concomitant malformations, which primarily affect the eye (aniridia or missing iris) or the urethra (urogenital malformations).

In addition, a Wilms tumor is primarily characterized by painless tumor swelling in the abdominal wall area and is only rarely accompanied by pain, hematuria ( blood in the urine ) or hypertension ( high blood pressure ).


The causes of a Wilms tumor have not yet been clarified. Due to the fact that a nephroblastoma can in many cases be associated with concomitant congenital malformations or genetic diseases such as Beckwith-Wiedemann syndrome , WAGR syndrome or Denys-Drash syndrome , genetic factors are assumed to be responsible for the manifestation of the tumor disease .

It is assumed that the so-called Wilms tumor gene WT-1, which plays an important role in the physiological formation of the kidney, and WT-2, which is located on chromosome 11 like WT-1, lead to the manifestation of a Wilms tumor could contribute.

In addition, analysis of the tumor cells revealed a DNA loss on the short arm of chromosome 11, which is normally responsible for tumor suppression.

Symptoms, Ailments & Signs

The Wilms’ tumor (also called nephroblastoma) is a special type of kidney tumor that occurs particularly in children. In 85 percent of cases, the children suffering from a Wilms’ tumor are younger than five years. In 11 percent of all cases, the Wilms’ tumor occurs without symptoms and was discovered by chance during a preventive examination.

If the Wils tumor shows symptoms, the main symptom is a painless bulging of the abdomen, i.e. a bulging of the abdominal wall. In some cases, the children complain of pain. This bulging, “fat” belly is often not recognized as a symptom but seen as a sign of well-being. Rarely, the child has blood in their urine (hematuria).

Atypical symptoms that can accompany nephroblastoma are fever , vomiting , problems with the digestive system or high blood pressure (hypertension). The problems with the digestive system can be loss of appetite or alternating diarrhea and constipation .

In rare cases, an increased concentration of calcium in the blood can occur ( hypercalcaemia ). In rare cases, Wilms’ tumor also occurs in young or older adults. Here it can manifest itself through flank pain , weight loss and a sudden drop in performance.

Diagnosis & History

Since a Wilms tumor initially causes hardly any characteristic symptoms, the tumor disease is often diagnosed as part of a routine examination by palpating the abdominal area.

If a painless swelling is found, this can be a first indication of a Wilms tumor. Imaging methods such as sonography (ultrasound), computed tomography ( CT ), X-ray examination and magnetic resonance imaging ( MRI ) are used to confirm the diagnosis . These also serve to determine the size and localization as well as the spread of the tumor (detection of metastases).

In addition, the kidney function can be checked using a creatinine clearance (determining the creatinine concentration in the urine or serum) and a kidney function scintigraphy (nuclear medicine procedure). A Wilms tumor has a progressive course with rapid growth and tends to metastasize at an early stage. As a rule, however, the prognosis is good with early diagnosis and treatment, and in about 90 percent of cases the affected children can be cured in the long term.


Wilms’ tumor is the most common form of kidney cancer in children. If the tumor is discovered in time and treated adequately, there is a good chance that the patient will recover completely and that no serious complications will arise. Nevertheless, crises during therapy must be expected.

A very common complication that occurs with Wilms’ tumor is high blood pressure. The hormone-like enzyme renin, which is produced in excess, causes the lumen of the blood vessels to narrow, leading to an increase in blood pressure. In addition, kidney bleeding can occur because the membrane of Bowman’s capsule is injured.

The blood often collects first in the renal pelvis, blood clots can usually be found in the urine. If the internal bleeding is very severe, this can lead to a drop in blood pressure and the resulting loss of consciousness in the patient. A life-threatening circulatory collapse cannot be ruled out in the case of very severe internal bleeding.

As with many malignant growths, Wilms’ tumor is at risk of spreading. Metastases usually form in the lungs, leading to chest pain, shortness of breath, and bloody sputum in the patient before more serious complications develop.

When should you go to the doctor?

If children are showing unusual behavior, parents should always pay increased attention to the behavior or health developments in the child. A doctor should be consulted in the event of tearful behavior, severe restlessness or insomnia. If unnatural changes, swellings or bulges develop on the body, these must also be clarified as quickly as possible. If there are symptoms such as vomiting, nausea or problems with the digestive tract, the child needs medical care. Loss of appetite, constipation or irregular heart rhythm are warning signals from the body.

To consult a doctor, since with an unfavorable course of the disease there can be serious complications. If existing symptoms persist for a long time, new symptoms develop or the intensity of the irregularities increases, a doctor must be consulted immediately. There is a need for action if you have a fever, blood in your urine or have problems concentrating or paying attention.

Pain and adopting a protective posture should be examined and treated in more detail. If the physical and mental performance decreases, this indicates a health impairment. Sudden changes in particular are a cause for concern. If participation in social life decreases and if the child’s play instinct decreases within a short time, a doctor should be consulted. A doctor’s visit is also necessary if you lose weight.

Treatment & Therapy

The treatment of a Wilms’ tumor usually includes surgical removal of the tumor-bearing kidney (tumor nephrectomy) as well as chemotherapeutic and radiotherapeutic measures. The individual measures and their sequence are tailored to the age of the affected child, the nature of the tumor and the stage of development of the disease.

In children who are less than six months old, for example, the tumor-bearing kidney is surgically removed as a matter of principle. Before the surgical intervention, however, it should be checked whether the second kidney is fully functional. In older patients or in the presence of a larger nephroblastoma, the Wilms tumor is first reduced by chemotherapeutic measures before it is surgically removed as part of a tumor nephrectomy.

If both kidneys are affected, a surgical procedure is aimed at preserving the kidneys and, following the chemotherapy , only the remaining tumor residues and metastases are removed from the unaffected kidney tissue (tumor nucleation). In rare cases (e.g. advanced stage of the disease or high level of malignancy of the Wilms tumor), radiation therapy is also required in order to kill residual tumors or metastases that could not be removed surgically or chemotherapeutically.

Furthermore, after successful therapy, affected children should be regularly checked for recurrence (tumor recurrence) as part of follow-up examinations, especially within the first two years after the end of therapy.


Because the causes of Wilms’ tumor are unknown, nephroblastoma cannot be prevented. Children who are affected by genetic diseases that seem to promote tumor disease (including Beckwith-Wiedemann syndrome) should be examined by a doctor for a possible Wilms tumor if swelling occurs in the abdominal area. In individual cases, molecular genetic tests may be necessary to determine a predisposition (disposition) to a Wilms tumor.


Following the actual treatment of Wilms’ tumor, follow-up care for the affected children is necessary. If a solid tumor has been surgically removed, specialists in oncology and hematology at the children’s clinic take care of the follow-up treatment. In most cases, radiation treatment is no longer necessary after chemotherapy and surgery.

The extent and type of aftercare depends on the stage of the Wilms tumor. Since this time is extremely stressful for the affected children and their families, psychosocial care makes sense. Qualified psychotherapists show both the sick child and its parents and siblings how to deal better with the difficult situation.

The check-ups are also an important part of aftercare. They must take place regularly because the cancer can reoccur in the two years following therapy. If an ulcer actually shows up again, it can be treated early. The close-meshed examinations include sonography (ultrasound examination). Magnetic resonance imaging is also possible. If the suspicion of a recurrence is confirmed, this is treated again with chemotherapy.

Follow-up care also includes regular check-ups of the lungs using X-ray examinations. In the first two years after cancer therapy, there is a risk of metastases (secondary tumors) in the lungs. If there are no recurrences or metastases after five years, the child is considered cured and no more check-ups are required.

You can do that yourself

The development of the tumor disease occurs in most cases in children. Therefore, relatives and especially the parents are responsible for the best possible support of the patient in everyday life. Self-help measures focus on working closely and harmoniously with the treating medical team and following their instructions.

Studies show again and again that mental and mental stability is particularly important in overcoming the disease. Therefore, conflicts and stressful situations should be avoided as much as possible. The focus is on activities to promote joie de vivre and well-being. At the same time, the child should receive instruction and be supported as best as possible in the natural learning process.

The child should be sufficiently and comprehensively informed about the present illness and its consequences. The occurrence of possible symptoms should be discussed with the child so that situations of fear or panic can be reduced to a minimum. Since the disease is associated with numerous health restrictions and long-term therapy is required, the child must be emotionally prepared in good time for the further course of action. Contact with other children is important during this time and should therefore be encouraged. A joint exchange can be helpful in coping with the circumstances. Proximity to family members is also extremely important throughout the treatment period.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.