WILMS TUMOUR

Wilms' tumour : This is a rare childhood tumour, affecting 1 in 10,000 children. It represents 80% of all genitourinary tumours affecting children under 15 years. Males and females are equally affected. 20% are familial and 5% are bilateral. 75% present under the age of 5 years.

Pathology and staging
Wilms  tumour is a soft pale grey tumour (it looks like brain). It contains blastema, epithelial and connective tissue components.
Mutation or deletion of both copies (alleles) of the chromosome 11p WT-1 tumour suppressor gene results in tumourigenesis. The familial disease exhibits autosomal dominant inheritance, but is recessive at the cellular level. Affected family members harbour a germ-line WT-1 mutation, conferring susceptibility. One further ‘hit  is required, while two hits  are required to cause the sporadic disease. This explains why hereditary Wilms  tumours tend to develop multifocally and at a slightly younger age than sporadic counterparts.
Tumour staging relates to the relationship of the tumour to the renal capsule, excision margins, and local lymph nodes at nephrectomy, as well as the presence of soft tissue (typically lung) or bone metastases.

Presentation
90% have a mass; 33% complain of abdominal or loin pain; 30 - 50% develop haematuria; 50% are hypertensive; and 15% exhibit other anomalies such as hemihypertrophy, aniridia, and cryptorchidism.

Investigations
The first-line investigation for a child with an abdominal mass or haematuria is ultrasound, which will reveal a renal tumour. Further diagnostic imaging and staging is obtained by CT, including the chest.

Treatment and prognosis
Children with renal tumours should be managed by a specialist paediatric oncology centre. Staging nephrectomy, with or without pre-operative or post-operative chemotherapy, remains the mainstay of treatment. The chemotherapy most frequently used is actinomycin D, vincristine and doxorubicin. Survival is generally good, at 92% overall, ranging from 55% to 97% according to stage and histology.