Wilms tumor is a complex mixed embryonal tumor of the kidney. Although it is usually seen in children between the ages of 2-5, it can also be seen in newborn, adolescent and adult age groups. It constitutes about 6% of childhood malignant tumors and is the second most common malignant abdominal tumor in children. It can originate from a single kidney or from both kidneys together. Bilateral Wilms tumor constitutes 7% of all cases. It may be associated with other congenital anomalies affecting the genito-urinary system. Its association with various syndromes has also been described.
Only 1-2% of patients with Wilms tumor have a family history. The familial predisposition is autosomal dominant.
Wilms tumor is surrounded by a prominent capsule. The cut surface is gray-pink.
Diagnosis: Most of the patients apply to the physician when the abdominal mass draws the attention of the family.
General malignancy symptoms such as loss of appetite, weight loss, anemia may also be seen.
Abdominal examination reveals a smooth-surfaced tumoral mass. In 30% of the patients, hematuria is observed in the urine.
Solid and cystic structures can be distinguished in ultrasonographic examination. It should be investigated whether the tumor involves the renal vessels and the lower main vein.
In the medicated kidney film (I.VP) of patients with Wilms tumor, deformity (distortion) is seen in the pelvicalyceal structures of the kidney. In some cases, no filtration is observed in the kidney with the tumor
Computed tomography and MR (Magnetic Resonance) methods The relationship of the tumoral mass with surrounding organs and great vessels can be viewed in detail.
In cases involving both kidneys, it is necessary to reveal the relationship between the vessels and the tumor in detail. For this purpose, renal angiography may be required. It should be visualized in the lower main vein.
Lung metastases should be examined with computed tomography in delayed cases.
Treatment: The main principle of treatment is the complete removal of the tumor. Suspicious lymph nodes that may be in the same area should be removed.
However, before removing the tumor, it should be ensured that the contralateral kidney is safe. The ureter (urinary tract) of the kidney with tumor should be followed up to the bladder (urinary bag) and removed.
In tumors involving both kidneys, surgical intervention should be planned to leave as much intact kidney tissue as possible.
The same surgical principles apply to horseshoe kidneys.
Tumor; clinical data, laparotomy and histopathological examination results are evaluated and staging is made. If necessary, chemotherapy and radiotherapy program is planned according to the stage of the tumor. Radiotherapy may be required in distant metastatic areas. Chemotherapy and radiotherapy details will not be entered here.
MESOBLASTIC NEPHROME:
It is impossible to differentiate it from Wilms tumor in physical and radiological examinations. Definitive diagnosis is made by histopathological examination. It is usually seen in infants younger than six months.
Although it is a benign tumor, it has been reported in metastasizing cases. When it is removed with the tumor capsule without being damaged (without spreading around), there is no chance of reoccurrence. Also, it does not require chemotherapy and radiotherapy.
There are those who recommend chemotherapy for ten weeks in types with excessive mitosis.
NEFROBLASTOMOSIS: This type usually refers to the abnormal presence of embryonal kidney tissue, which may be associated with the development of Wilms tumor. With short-term chemotherapy, it rapidly shrinks and stops growing and turns into a nodule. However, it may be necessary to follow up with Computed Tomography from time to time. Because it is not known whether chemotherapy reduces the frequency of transformation into Wilms tumor in the future.
MULTICISTIC NEPHROBLASTOM: Kidney tumors rarely contain cysts. Some of the cysts may be associated with Wilms tumor. Most of the reported multicystic nephroblastoma cases are under the age of one. When this type of tumor is encountered, it can be considered as benign. However, if there are definite signs of Wilms tumor, chemotherapy should be applied.
RENAL CELL CARCINOMA: This tumor is rare in the first decade of life. Although rare, there are cases reported after puberty in children. It usually manifests itself as a mass and blood in the urine. Complete removal of the tumor is sufficient for treatment.
