After Burkitt's lymphoma, nephroblastoma is the commonest solid tumour of childhood in Africa (in Caucasians it is the fourth commonest). The tumour is a hamartoma, which arises from embryonal kidney cells and spreads locally through the capsule of the kidney to neighbouring nodes (often fairly late), as well as to a child's liver, his lungs, and sometimes his bones.
A young child presents with a fairly rapidly growing and usually painless mass on one side of his abdomen. In 70% of cases he is under two years old, and is seldom over 6. In 5% of cases the mass is present at birth, and in 5% it is bilateral. He rapidly loses weight and may be febrile (50% of cases). Haematuria is late. If you see him early enough, his kidney can be removed, and his prognosis is good.
NEPHROBLASTOMA THE DIFFERENTIAL DIAGNOSIS includes hydronephrosis (often bilateral), polycystic disease of the kidneys (uncommon, haematuria is usual), or a neuroblastoma displacing the kidney downwards (rare in Africa).
CAUTION ! The diagnosis often delayed because the swelling is mistaken for an enlarged spleen. Feel for a splenic notch on the anterior border. Percuss the mass. Malarial splenomegaly is seldom marked before the age of 2.
Look for other congenital anomalies (eye defects, hemihypertrophy, and urinogenital anomalies), which are sometimes associated with a nephroblastoma.
STAGING and PROGNOSIS. A nephroblastoma is always fatal without treatment. The survival figures below are for a combination of nephrectomy, radiotherapy, and chemotherapy. Long- term cures for the first three stages are common.
Stage One Growth is confined to the kidney, and can be removed in toto. 95% 4 year survival.
Stage Two Growth penetrates the capsule, but is entirely excised. 85% 4 year survival.
Stage Three A large tumour, not excised completely, but confined to the abdomen. 85% 4 year survival.
Stage Four Growth widespread, with secondaries beyond the abdomen.
Bilateral disease Palliation only is possible.
MANAGEMENT. Don't try to remove the child's kidney, unless you are skilled. Diagnose the condition clinically, and refer him for investigation, nephrectomy, and chemotherapy, and perhaps radiotherapy. If this is not available, it is acceptable to rely on nephrectomy and chemotherapy. It is not acceptable to leave his kidney in and to give him chemotherapy only.
If you are sure of the diagnosis from the IVU and are unable to refer him quickly, you can give him one dose of the regime, but do refer him quickly.
If you are able to remove his kidney, give him the following chemotherapy.
Stage One Give him vincristine 1.4 mg/m['2] (maximum dose 2 mg) intravenously every 21 days, for 3 to 6 months. Either start 2 or 3 days after nephrectomy, or if the tumour is very large, give the first dose a week before operating, to reduce the size of the tumour.
Stages Two and Three Give him vincristine 1.4 mg/m['2] (maximum dose 2 mg) intravenously. And actinomycin D 1 mg/m['2] intravenously. Give him one dose of each of these every 21 days for 15 months. Or, give him the actinomycin only.