ASSOCIATION OF EXTRARENAL WILMS-TUMOR WITH A HORSESHOE KIDNEY

Nephroblastoma (Wilms' tumor) is the most common renal malignancy in c hildhood. Extrarenal Wilms' tumor is uncommon, and the diagnosis is al most always postsurgical. The authors report two cases, located in the sigmoid mesocolon, one of these having an associated horseshoe kidney . Both were treated with excision followed by chemotherapy. They are n ow 36 months and 7 months postchemotherapy, respectively, and are symp tom and recurrence free. Both had favorable histological findings. Ass ociation with a horseshoe kidney raises an important issue regarding t he histogenesis of these tumors. The authors believe that there is a n exus between the fusion of metanephric blastema during the sixth to se venth week of intrauterine life and the ''ectopic'' metanephric blaste ma cells that may give rise to extrarenal Wilms' tumor. Association wi th a horseshoe kidney with an extrarenal Wilms' tumor has been reporte d on five previous occasions. The authors closely examine the link bet ween the two. J Pediatr Surg 33:935-937. Copyright (C) 1998 by W.B. Sa unders Company.