Prenatal sonographic diagnosis of multicystic congenital mesoblastic nephroma.

The authors report an unusual presentation of congenital mesoblastic nephroma as a multilocular cystic renal lesion. Prenatal sonography revealed a unilateral, encapsulated, multilocular cystic mass with solid components measuring 5.7 × 5.4 × 4.3 cm in the left renal fossa. There was no increase in vascularity and no signs of hydrops fetalis. On the forth postnatal day left-sided radical nephrectomy was performed and histopathological examination revealed cellular type congenital mesoblastic nephroma. A multicystic appearance is rare as the vast majority of prenatally diagnosed congenital mesoblastic nephroma cases presented in the literature are of the classic type with solid homogenous or heterogenous appearence.