Nephroblastoma (Wilm's tumour)

Related Subjects: |Pyelonephritis and Urosepsis (UTI) |Pyonephrosis |Perinephric abscess |Acute Kidney Injury (AKI) / Acute Renal Failure |Renal/Kidney Physiology |Chronic Kidney Disease (CKD)

🧒🌱 Wilms tumour (Nephroblastoma) – The average newly found tumour is often many times larger than the kidney it arises from. Most are detected before metastasis to other organs.

📖 About

• Most common renal tumour of childhood (peak 1–4 years).
• Median age at presentation ~3.5 years 👶.
• 95% are unilateral; 5% bilateral.

🔗 Associations

• Beckwith–Wiedemann syndrome 🧬
• Aniridia 👁️
• GU malformations (e.g. cryptorchidism) ⚕️
• WAGR syndrome: Wilms tumour, Aniridia, GU malformation, Retardation 🧩
• Hemihypertrophy (asymmetric body overgrowth) ↔️

🧬 Aetiology & Genetics

• Embryonal tumour of undifferentiated mesodermal tissue.
• Arises from primitive metanephric blastema cells 🌱.
• Often linked to WT1 tumour suppressor gene deletion on Chromosome 11.

🩺 Clinical Features

• Large, smooth, firm, usually painless abdominal mass 🤲.
• Abdominal pain (sometimes due to intratumoural haemorrhage).
• Loss of appetite, weight loss, fatigue.
• Microscopic or macroscopic haematuria 💧.
• Hypertension due to renin secretion or renal compression 📈.
• Occasionally fever, anaemia, or varicocele.

🔎 Investigations

• Urinalysis: May reveal haematuria.
• USS abdomen: Initial imaging – distortion of renal pelvis, hydronephrosis.
• CT/MRI abdomen + chest: For staging and detecting pulmonary metastases (commonest site 🌬️).
• Histology: Triphasic pattern = blastemal, epithelial, and stromal elements.

📊 Staging (Simplified)

• I: Tumour confined to kidney
• II: Extrarenal spread, but completely resectable
• III: Residual abdominal disease post-surgery
• IV: Distant metastases (lungs, liver, bone, brain)
• V: Bilateral disease

💊 Management

• 🚫 Avoid biopsy (risk of tumour spillage).
• Nephrectomy = cornerstone of treatment.
• Chemo: Vincristine + Actinomycin D (early stage); add Doxorubicin for advanced stages.
• Radiotherapy: For stage III+ disease or unfavourable histology.
• Supportive care: manage hypertension, anaemia, and pain.

📈 Prognosis

• Excellent prognosis in most cases – overall 5-year survival ≈ 90% 🌟.
• Poorer outcome with anaplastic histology, bilateral disease, or advanced stage.

🧑‍🏫 Exam Tip

Think of Wilms tumour when a child presents with an asymptomatic abdominal mass. The classic association set (WAGR + Beckwith–Wiedemann + aniridia) is high-yield for exams 📚. Remember: Biopsy is avoided – definitive diagnosis and treatment is by nephrectomy + chemo.

Cases - Nephroblastoma (Wilms’ tumour)

• Case 1 - Classic abdominal mass 👶: A 3-year-old girl is brought by her mother who noticed a painless swelling in the abdomen while bathing her. Exam: firm, smooth, non-tender mass in the left flank that does not cross the midline. BP: 140/95 mmHg. Ultrasound: renal mass. Diagnosis: Wilms’ tumour. Managed with nephrectomy + chemotherapy.
• Case 2 - Haematuria & hypertension 🩸: A 4-year-old boy presents with visible haematuria, abdominal pain, and irritability. Exam: right-sided abdominal mass, elevated BP. CT scan: large renal mass confined to kidney, no metastases. Diagnosis: Wilms’ tumour with haematuria and hypertension. Managed with surgery + adjuvant chemo; prognosis excellent.
• Case 3 - Syndromic association 🧬: A 2-year-old girl with known Beckwith–Wiedemann syndrome (macroglossia, hemihypertrophy, neonatal hypoglycaemia) is found to have an abdominal mass on routine screening ultrasound. Diagnosis: Wilms’ tumour in syndromic child. Managed with multidisciplinary oncology input, nephrectomy, and chemotherapy; long-term surveillance required.

Teaching Point 🩺: Wilms’ tumour is the most common renal malignancy of childhood (peak age 2–5 years). Key features: painless abdominal mass, haematuria, hypertension. Associations: Beckwith–Wiedemann syndrome, WAGR syndrome, Denys–Drash syndrome. Diagnosis: ultrasound/CT, avoid biopsy (risk of tumour spillage). Management: nephrectomy + chemotherapy ± radiotherapy. Prognosis is excellent if localised.