Makindo Medical Notes

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

The average newly found Wilms tumour is many times larger than the kidney in which it started. Most Wilms tumour are found before they have spread (metastasized) to other organs.

About

• The most common renal tumour in children aged 1-4 years.
• Median age at presentation: 3.5yrs. 95% are unilateral.

Associations

• Beckwith–Wiedemann syndrome
• Aniridia
• GU malformations (eg cryptorchidism)
• Retardation (WAGR).

Aetiology

• Undifferentiated mesodermal tumour of the intermediate cell mass.
• Arises from embryonal renal tissue.
• More common in children with associated conditions such as aniridia (absence of the iris) and hemihypertrophy (asymmetric overgrowth of one side of the body).

Genetics

• Associated with the deletion of the tumour suppressor gene WT1 located on Chromosome 11.

Clinical Features

• Often presents as a large, asymptomatic abdominal mass.
• Poor appetite and weight loss are common symptoms.
• Patients may experience abdominal pain and microscopic haematuria.
• Hemorrhage into the tumour mass can cause significant pain.
• Hypertension may also be present.

Investigations

• Urinalysis: May show macroscopic haematuria.
• Imaging: Ultrasound (USS) renal pelvis distortion; hydronephrosis, CT, or MRI of the abdomen is used to stage the tumour, assess local spread, and detect lung metastases. Note that 5% of cases are bilateral.
• Histology: Demonstrates the proliferation of metanephric blastema cells, which are primitive embryologic cells of the kidney.

Staging

• Tumour confined to the kidney
• II Extrarenal spread, but resectable
• III Extensive abdominal disease
• IV Distant metastases
• V Bilateral disease

Management

• The prognosis is generally good, but it depends on the stage at diagnosis.
• Avoid biopsy; nephrectomy + vincristine and actinomycin for 4 weeks pre-op can cure. Chemotherapy is used in all tumours. A 2-drug regimen is recommended for early Wilms’ (without radiotherapy); more advanced stages need a 3-drug regimen + radiotherapy.
• Overall, the 5-year survival rate is approximately 90% long-term survival..