Wilms Tumour

Overview – Wilms Tumour

Wilms tumour, also known as nephroblastoma, is the most common renal malignancy in children, typically presenting between the ages of 2 and 5. This embryonal tumour arises from nephrogenic blastemal cells and can present with abdominal swelling, haematuria, or systemic symptoms. While often detected early due to parental awareness of abdominal masses, its clinical relevance lies in the potential for bilateral involvement, paraneoplastic syndromes, and metastasis. This page summarises the high-yield features of Wilms tumour, including its genetic basis, clinical presentation, diagnostic pathway, and current management strategies.

Definition

Wilms tumour (nephroblastoma) is a malignant renal tumour of embryonic origin that most commonly affects children under the age of 5. It arises from primitive renal cells (blastemal origin) and may be unilateral or bilateral.

Aetiology

Sporadic

• 80% of cases
• Usually unilateral

Familial

• 20% of cases
• More likely to be bilateral
• Associated with genetic mutations on chromosome 11
  • WT1 (Wilms Tumour 1 gene)
  • WT2 (Wilms Tumour 2 gene)

Morphology / Pathophysiology

• Classified as a blastoma — tumour of embryonic renal cells
• Gross features:
  • Large, pale, grey-white tumour replacing normal renal parenchyma
  • Well encapsulated
  • Areas of focal haemorrhage and necrosis

Clinical Features

• Most common renal tumour in children aged 2–5 years
• Common symptoms:
  • Palpable abdominal mass
  • Abdominal pain
  • Haematuria (may be intermittent)
  • Anorexia, nausea, and vomiting
  • B symptoms: fever, weight loss, night sweats

Investigations

• Abdominal ultrasound
  • First-line for diagnosis
  • Assesses renal vein involvement
• Abdominal CT scan
  • For local staging
• Chest CT scan
  • To evaluate for pulmonary metastases
• Ultrasound-guided needle biopsy
  • Confirms diagnosis histologically

Management

• Surgical nephrectomy (partial or radical depending on staging and laterality)
• Chemotherapy – often pre- and post-operative
• Radiotherapy – used selectively in higher-stage or metastatic disease

Complications

Metastasis

• May spread to:
  • Lungs (most common site)
  • Liver, bones, and brain

Paraneoplastic Syndromes

• Increased renin secretion → secondary hypertension

Prognosis

• Generally good with prompt treatment
• 5-year survival rate: ~80%
• Prognosis is worse in bilateral, advanced stage, or anaplastic subtypes

Differential Diagnosis

• Neuroblastoma (commonly crosses midline, unlike Wilms)
• Multicystic dysplastic kidney
• Hydronephrosis
• Renal cell carcinoma (rare in children)

Summary – Wilms Tumour

Wilms tumour is a common childhood renal malignancy that presents with abdominal mass, pain, haematuria, and systemic symptoms. It is typically unilateral and sporadic, though familial forms exist. Diagnosis is established through imaging and biopsy, and treatment involves a combination of nephrectomy and chemotherapy. Prognosis is favourable in most cases. For a broader context, see our Renal Overview page.