nephroblastoma

Nephroblastoma, known medically as Wilms tumor, is a malignant kidney tumor that most often arises in children. It is the most common renal malignancy in pediatric patients, with a peak incidence around ages 2 to 4.

Most tumors originate from embryonic kidney tissue and result from genetic and epigenetic changes. The WT1 gene on chromosome 11p13 is involved in a subset of cases. Syndromic associations include WAGR syndrome (Wilms tumor, aniridia, GU anomalies, developmental delay), Denys-Drash, and Beckwith-Wiedemann syndrome.

Clinically, patients commonly present with an asymptomatic abdominal mass. Other symptoms can include abdominal pain, hematuria, hypertension, fever, or signs related to metastasis such as cough or dyspnea in advanced disease.

Diagnosis typically begins with abdominal ultrasound, followed by cross-sectional imaging (CT or MRI) to define extent and assess metastasis, especially to the lungs. Chest imaging is essential. Biopsy is not routinely performed preoperatively due to the risk of tumor rupture; diagnosis is usually confirmed after nephrectomy. Histology is classified as favorable (low risk) or anaplastic (unfavorable).

Treatment combines surgery and chemotherapy, with radiotherapy added for selected cases. Most patients undergo nephrectomy with regional lymph node sampling, followed by systemic chemotherapy (commonly vincristine and actinomycin D; doxorubicin added for higher stage or unfavorable histology). Preoperative chemotherapy is used in some treatment protocols to shrink large tumors.

Outcomes are favorable with contemporary multimodal therapy, especially for localized disease, with five-year survival exceeding 90% in favorable-histology cases. Prognosis worsens with metastasis or anaplastic histology. Long-term follow-up addresses renal function, blood pressure, growth, and risk of late effects or secondary malignancies.