Unusual association of Wilms' tumor with cystic diseases of kidney: A pathologic surprise.

Wilms' tumor (or nephroblastoma) is the most common renal malignancy in the pediatric population which consists of blastemal, epithelial, and stromal elements in variable proportions. The occurrence of renal cysts in children and infants is a rare phenomenon and is possibly an outcome of developmental aberrations in mesonephric blastema. The coincidental association of nephroblastoma with renal cysts is a very rare finding. Here, we describe two cases of Wilms' tumor with an unusual association between glomerulocystic kidney disease and multicystic dysplastic kidney.