Wilms' tumor may be a rare presentation of ovarian neoplasms in girls

Extrarenal Wilms' tumor is a rare malignant disorder. It represents 0.5-1% of Wilms' tumor. Management for ERWT is challenging regarding its pathological diagnosis, staging, treatment and prognosis. Here we report a 4 years old girl, presented with huge pelvi abdominal mass originating from the left ovary which was seen by radiologic assessment as a large lobulated heterogeneously enhancing mixed solid and cystic retroperitoneal mass away from both kidneys, occupying most of the abdomen with pelvic extension; it was displacing bowel loops and pancreas, measuring 13 x 15 x 16 cm without evidence of enlarged lymphadenopathy. The mass was diagnosed postoperatively as an extrarenal Wilms' tumor proved by immunohistochemical staining for Wilms' Tumor1 (WT1) with the negative reaction for other markers that exclude other diagnostic possibilities. The patient had an aggressive presentation and advanced disease. The diagnosis was difficult due to the lack of specific radiologic stigmata and aberrant origin. She was treated with aggressive chemotherapy to suit the advanced stage of her disease and unfavorable histology pattern.