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Wilms tumor
Last reviewed: 23.04.2024
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Wilms tumor in children (embryonic nephroma, adenosarcoma, nephroblastoma) is a malignant tumor that develops from pluripotent renal bookmarking - a metanephrogenic blastema.
The Wilms tumor is found at a frequency of 7-8 per 1 million children under the age of 15 regardless of sex. Almost all kidney tumors in children are represented by Wilms' tumor. According to the occurrence in childhood, nephroblastoma ranks fourth among all tumors.
Pathological anatomy
Nephroblastoma is a solid tumor, covered with a capsule. For quite a long time the tumor grows expansively, not germinating the capsule and not metastasizing. At the same time, it can acquire very large dimensions, squeezing and pushing out surrounding tissues. In the thickness of the tumor tissue, small foci of fresh and old hemorrhages are revealed. Further development of tumor growth leads to capsule germination and metastasis.
Epithelial and side elements are detected histologically. Epithelial elements are represented by solid fields or strands of cells, in the center of which tubules resembling renal tubules are formed. Between the solid fields there is a loose fibrous tissue - a stroma, in which various mesodermal derivatives can exist (striated and smooth muscle fibers, fatty tissue, cartilage, vessels, and sometimes derivatives of ectoderm and neural plate).
In the world literature, several morphological variants of Wilms' tumor are distinguished, which are considered to be prognostically unfavorable and in 60% of cases cause a fatal outcome (in general, these signs are revealed in 10% nephroblast).
Anaplasia is a histological variant, in which a high variability in the size of cell nuclei with anomalous mitotic structures and hyperchromasia of enlarged nuclei is determined. This variant occurs in children aged about 5 years.
The rhabdoid tumor consists of cells with fibrous eosinophilic inclusions, but does not contain cells of the true striated muscle. It occurs in the smallest children.
Clear cell sarcoma - contains spindle-shaped cells with a vasocenter structure. It dominates in boys and often metastasizes to bone and brain.
Metastasis occurs mainly in the lungs, as well as in the liver and lymph nodes.
Symptoms of Wilms tumor in children
From the classical triad of signs of renal tumors - hematuria, palpable tumor and abdominal pain syndrome - Wilms tumor is most often initially manifested by palpable formation in the abdominal cavity. Pain and hematuria are revealed later. In 60% of cases with time arterial hypertension joins. In addition, non-specific signs (fever, cachexia, etc.) can be observed.
The average age at the time of diagnosis is 3 years. It should be borne in mind that Wilms' tumor is often combined with congenital anomalies of the genitourinary system, sporadic aniridia and hemihypertrophy. Familial forms of Wilms tumor are known, which are characterized by a high incidence of bilateral tumor damage and more frequent congenital anomalies. If one of the parents reveals a family or bilateral Wilms tumor, then the child's probability is about 30%.
Depending on the degree of spread of the tumor, 5 stages of the tumor process are isolated. At the first stage, the process is limited to the kidney and the tumor usually does not germinate the capsule. The tumor can be removed without rupturing the capsule, morphologically, there is no tumor tissue at the edge of the drug. At stage II, the tumor spreads beyond the kidney, can be completely removed. Morphologically, tumor cells can be found in pararenal tissue. At the III stage of tumor growth, non-hematogenous metastasis occurs within the abdominal cavity (periarterial and in the kidneys of the kidney lymph nodes, tumor implants on the peritoneum, the tumor germinates peritoneal cellulose, and morphological investigation reveals tumor cells along the edge of the drug). At the IV stage hematogenous metastasis of the tumor into the lungs, bones, liver, CNS is noted. At stage V, the tumor spreads to the second kidney.
Diagnosis of Wilms tumor in children
The detection of palpable formation in the abdominal cavity, especially in combination with hematuria, requires the exclusion of nephroblastoma. In a small percentage of cases, the only manifestation of pathology may be hematuria. With ultrasound and excretory urography, intracranial localization of the neoplasm, destruction of the collecting system of the kidney is detected. It is possible to detect calcifications in place of old hemorrhages and signs of thrombosis of the inferior vena cava.
Differential diagnosis is performed with other tumors, primarily with the neuroblastoma of the retroperitoneal space emanating from the adrenal glands or the paravertebral ganglia.
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Treatment of Wilms tumor in children
A complex treatment is provided, including nephrectomy, polychemotherapy and radiotherapy.
Nephrectomy is performed immediately after diagnosis, even if metastases are present.
The tactics of treatment largely depends on the stage of the disease. At I-III stage, nephrectomy is performed, and it is important not to rupture the intact capsule of the kidney, because this significantly worsens the prognosis. At II-III degree in the postoperative period the course of irradiation is conducted. At IV-V degrees on individual indications preoperative irradiation of a tumor is possible.
Polychemotherapy is performed by all patients in the postoperative period. Wilms tumor is highly sensitive to vincristine and actinomycin D, which are applied in combination. In the most prognostically unfavorable cases, ifosfamide and anthracyclines are included in the therapy.
In the United States, the most widely used protocol was the treatment of the combined National Research Group NWTS; in the European countries the protocol SI0R is developed. The effectiveness of therapy on each of them is approximately the same.
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Forecast
The prognosis is relatively favorable in children aged under 2 years and with a tumor mass of less than 250 g. Tumor recurrences and the presence of histologically unfavorable signs worsen the prognosis.
According to the data of BA Kolygin (1997), the 20-year survival rate after complex therapy is 62.4%, and in recent years, with adequate protocol of therapy, the percentage of cure is 70-75% (8-year survival).