Adult extrarenal Wilms' tumour: A case report and review of literature.

Whilst only fifteen cases of extrarenal Wilms' tumour (EWT) have been documented in adults, only two previous cases were located in the retroperitoneal space. We report a case of a 21-year-old Saudi female who presented with severe abdominal pain associated with a large solid tumour filling most of the left side of the abdomen and extending across the midline to the right side. Following surgical removal of this retroperitoneal mass, histopathological examination showed the classical features of Wilms' tumour. Both kidneys did not show any primary lesion. The local tumour recurrence responded to Wilms' tumour chemotherapy regimen. The literature on EWT is also reviewed, and the possible mechanism of histogenesis is discussed.