Definition
Wilms' tumor (or nephroblastoma) is a malignant neoplasm of the kidney, characteristic of the pediatric age.
The age group most affected is between the first and fifth years of life, but the disease can also occur in older children and, rarely, in adulthood.
Wilms' tumor is of embryonic origin, that is it derives from the primitive renal sketch.
The onset is mainly sporadic and only 2% of cases can be hereditary.
In pathogenesis, various genetic abnormalities are implicated. In particular, the neoplastic process can be triggered by mutations and deletions of the WT1 gene (located on chromosome 11), which normally intervenes in the differentiation of the nephroblasts, during the first phases of embryonic development of the kidney. Other genetic aberrations associated with Wilms' tumor include deletion of chromosome 16 and duplication of chromosome 12.
The nephroblastoma develops mainly in one kidney; Synchronous bilateral tumors occur in approximately 5% of patients. Sometimes the disease may occur in association with congenital anomalies of the urogenital tract (renal hypoplasia, cystic disease, hypospadias and cryptorchidism), hemihypertrophy (asymmetry of the body) or specific syndromes (Beckwith-Wiedemann and Denys-Drash).
Most common symptoms and signs *
- Anemia
- Anorexia
- Asthenia
- Pain in a hip
- Abdominal pain
- Kidney pain
- Temperature
- Hypertension
- Abdominal mass
- Weight loss
- Blood in the urine
Further indications
Often, Wilms' tumor manifests itself as a mass in the palpable and painless abdomen (unilateral or bilateral). In about 20% of cases, the first sign of illness is the appearance of hematuria (blood in the urine), which indicates an involvement of the renal collecting tubules.
Patients with nephroblastoma may also experience abdominal pain, fever, anorexia, weight loss and fatigue.
If the compression of the renal peduncle (complex of vascular formations coming from the kidney or directed to it) causes an ischemia of the organ parenchyma, an increase in arterial pressure may occur.
At other times, the manifestation of the disease can be dramatic, as the tumor can rupture inside the abdomen causing bleeding.
Wilms' tumor is often found during a pediatric checkup. The diagnostic assessment involves performing an abdominal ultrasound (indicating whether the mass is cystic or solid and whether the renal vein or inferior vena cava are involved). Abdominal CT is necessary to establish the extent of the tumor and verify the spread to the regional lymph nodes, the contralateral kidney, the liver or the lung. The diagnosis is confirmed by mass biopsy.
Prognosis depends on the stage of the tumor at diagnosis (localized kidney disease or diffusion to other organs), histological features (favorable or unfavorable) and patient age, but is generally good in children.
Treatment may include surgical resection and chemotherapy (with vincristine and actinomycin D), with or without radiotherapy. Children with more advanced disease are also treated with doxorubicin.
Other frequently used drugs include cyclophosphamide, ifosfamide and etoposide. Children with very large unresectable tumors or bilateral tumors are candidates for chemotherapy followed by re-evaluation and, when possible, resection.
