Renal hypoplasia and postnatally acquired cortical loss in children with vesicoureteral reflux.

We reviewed histologically 86 nephrectomy specimens from patients with vesicoureteral reflux (with or without ureterovesical obstruction) to investigate the relationship between coexisting hypoplasia and postnatally acquired cortical damage. Hypoplasia was assessed independently of the acquired cortical loss using medullary ray glomerular counting. Severe hypoplasia (glomerular number < 25% of normal) was detected in 47 of 86 patients. These patients underwent nephrectomy at a significantly younger age than those with minimal or no hypoplasia (P < 0.01). There was no significant relationship between the severity of hypoplasia and the presence or absence of obstruction. Severe acquired cortical loss was found in 68 of 86 patients. There was no significant association between the severity of cortical loss and the presence or absence of obstruction, age at nephrectomy or degree of coexisting hypoplasia. The findings suggest a strong association of hypoplasia and vesicoureteral reflux. Therefore, early postnatal presentation with minimal renal function need not necessarily reflect a failure of management but rather a pre-existing limitation of renal capacity. Furthermore, in a significant proportion of fetuses with ultrasonographic evidence of urinary tract abnormality, renal pathology may be present prior to the time at which in utero surgical intervention may be considered.