Causes and pathogenesis of Wilms tumor
Last reviewed: 23.04.2024
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Wilms tumor in 60% of cases is the result of somatic mutation, 40% of Wilms tumors are caused by hereditary-deterministic mutations. Great importance in the pathogenesis of this tumor is given to mutations of recessive suppressor genes WT1, WT2 and p53, located in the 11th chromosome. According to the two-stage theory of carcinogenesis Knudson, the starting mechanism of the appearance of the Wilms tumor can be considered a mutation in the germ cell, and then the alteration of the alternative gene in a homologous chromosome. In addition to idiopathic aberrations, Wilms' tumor can become a manifestation of such hereditary syndromes as Beckwith-Wiedemann syndrome, WAGR (Wilms tumor, aniridia, urogenital abnormalities and mental retardation), hemygypertrophy, Denys-Drash syndrome (intersex disorders, nephropathy, Wilms tumor) and Le-Fraumeni syndrome.
Wilms tumor pathology
The classical histological structure of the Wilms tumor is represented by three main components: blastoma, stromal and epithelial. The ratio of the content of each of them in the tumor can vary significantly. In 3-7% of tumors, anaplastic changes are detected. Depending on the proportion of anaplastic cells in the tumor, focal (less than 10% of cells) and diffuse (more than 10% of cells) anaplastic forms are isolated. Diffuse anaplasia is associated with an extremely unfavorable prognosis.
Growth and metastasis of Wilms tumor
Wilms tumor is characterized by rapid local invasive growth. In 6% of cases, Wilms' tumor spreads through the lumen of the renal and lower hollow veins with the formation of tumor thrombi. Wilms tumor metastasizes by lymphogenous and hematogenous pathways. Lymphogenous metastases affect regional retroperitoneal lymph nodes.
Further, a tumor with lymph flow can be spread along the thoracic duct upward with the development of lesions of supraclavicular lymph nodes to the left. The most common target for hematogenous metastasis is light. It is also possible metastatic damage to the liver, bones, skin, bladder, sigmoid colon, orbit, spinal cord, contralateral kidney.
Classification of Wilms tumor
To determine the prevalence of malignant process and standardize treatment approaches to the treatment of nephroblastoma in children, most of the world's oncology clinics use the classification of the national Wilms tumor research group.
Classification of the nephroblastoma of the National Cancer Institute of Wilms tumor research
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Stage
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Characteristics of the tumor
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| I | The tumor is bounded by the kidney and completely removed. The capsule of the kidney is intact, the integrity of the tumor is not violated during removal. No residual tumor |
| II | The tumor spreads through the kidney capsule but is completely removed. There may be a partial ingression of tumor elements into the lateral canal, or a tumor biopsy may be performed. Extra-venous vessels may contain a tumor or may be infiltrated by a tumor |
| III | Residual non-hematogenous tumor in the abdominal cavity, lymph node involvement, peritoneal dissemination or tumor along the edge of the operative incision, or the tumor is not completely removed |
| IV | Hematogenous metastases to the lungs of the bone, brain and other organs |
| V | Bilateral renal disease at the time of diagnosis |
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