Universal nephroblastomatosis with bilateral hyperplastic nephromegaly in siblings.

We present an unusual renal developmental disorder in a female infant and male sibling born in a subsequent pregnancy. Both children had prenatally diagnosed bilateral nephromegaly and survived for 6 and 10 days after birth, respectively. Both infants demonstrated the presence of bilaterally large cerebriform kidneys with numerous small lobulations containing immature glomeruli admixed with primarily intralobar nephrogenic rests without Wilms tumor. The pathology was most consistent with universal nephroblastomatosis with nephromegaly, a rare entity described in only 4 cases and in only 1 of these as a possible inherited disorder.