Clinical meaning
Wilms tumor (nephroblastoma) is the most common primary renal malignancy in children, typically diagnosed between 2 and 5 years of age. It arises from embryonic kidney tissue (metanephric blastema) that fails to differentiate normally during fetal development, resulting in persistent nephrogenic rests that can undergo malignant transformation. The tumor originates within the renal parenchyma and can grow to a very large size before detection because the retroperitoneal space accommodates significant expansion. Wilms tumor is classified based on histology into favorable histology (approximately 90% of cases, with a cure rate exceeding 90%) and unfavorable or anaplastic histology (approximately 10% of cases, associated with a poorer prognosis due to resistance to chemotherapy). The tumor may be unilateral (affecting one kidney, approximately 93% of cases) or bilateral (affecting both kidneys, approximately 5-7% of cases). Several genetic mutations are associated with Wilms tumor, including mutations in the WT1 gene on chromosome 11p13 and the WT2 gene on chromosome 11p15.5. Wilms tumor is also associated with congenital anomalies and syndromic conditions including WAGR syndrome (Wilms tumor, Aniridia, Genitourinary anomalies, and intellectual disability), Beckwith-Wiedemann syndrome (macroglossia, omphalocele, visceromegaly, and hemihypertrophy), and Denys-Drash syndrome (male pseudohermaphroditism and progressive nephropathy). The single most critical nursing safety point is that the abdomen of a child with suspected or confirmed Wilms tumor must NEVER be palpated because manipulation can cause tumor rupture, seeding of malignant cells into the peritoneal cavity, hemorrhage, and upstaging of the disease. A sign reading DO NOT PALPATE ABDOMEN should be prominently displayed at the bedside. Treatment follows a multimodal approach: surgical nephrectomy is the primary treatment, followed by chemotherapy (vincristine, dactinomycin, and doxorubicin depending on stage) and radiation therapy for advanced stages. The National Wilms Tumor Study Group (now Children's Oncology Group) staging system guides treatment decisions based on surgical findings and extent of disease spread.