Familial extrarenal Wilms tumor.

BACKGROUND/PURPOSE: This study aimed to illustrate the first report of extrarenal Wilms tumor occurring in a family. MATERIALS AND METHODS: Retrospective case note review of 3 siblings, 2 of which presented with extrarenal Wilms tumor. Immunohistochemical analysis for WT1 gene product was performed together with molecular genetic linkage studies. RESULTS: A 3-year-old boy had excision of a right-sided extrarenal retroperitoneal Wilms tumor and nephrectomy followed by chemotherapy. At follow-up of 4 years, the boy was well and thriving. Aged 2 years, his sister developed a left-sided retroperitoneal extrarenal Wilms tumor. She had a tumor excision and nephrectomy followed by chemotherapy. She was well on follow-up more than a year after completion of treatment. Immunohistochemical analysis identified WT1 gene product within the tumor for both cases. Molecular genetic linkage studies showed no linkage between the index cases at FWT1 locus. Although possible linkage was demonstrated at WT1 locus, no mutation was found in the coding sequence and intron/exon boundaries of WT1 gene in index patient 1. A possible linkage between the index cases was also found at FWT2 locus. This could be a chance event because of the close relationship of the 2 patients. CONCLUSIONS: We could identify extrarenal Wilms tumor in a family for the first time. Immunohistochemical analysis showed WT1 gene products in both cases. Linkage studies for Wilms tumor genes within the family were inconclusive. The possible linkage between the 2 index cases may be a chance event.