Growth of the solitary kidney after nephrectomy in children with unilateral Wilms' tumor.
OBJECTIVE
We reviewed the length of the solitary kidney from all ultrasound examinations in 34 children who had undergone unilateral nephrectomy for Wilms' tumor, in order to determine the frequency of renal hypertrophy in this population. Standard sonographic criteria for nephromegaly were used.


METHODS
We generated a z-score for each measurement of the renal length, using an interpolated computer model based on published standards for sonographic renal length in relation to age. A retrospective age- and gender-matched control population of children with sonographically normal paired kidneys was generated from a departmental computerized pediatric uroradiology data base, and their ipsilateral renal lengths were compared with those of the study patients. Sonographic renal hypertrophy (SRH) was defined by two or more consecutive measurements of the renal length exceeding two standard deviations longer than the mean for the patient's age, with no later normal measurement.


RESULTS
Seventeen (50 %) of the 34 patients developed SRH. The latest measurements of the solitary kidney in the patients were significantly longer (mean z = 2.210) than in their controls (mean z = 0.040), even among the patients who did not develop SRH (patients' mean z = 1.000, controls' mean z = -0. 210, p < 0.001). Because boys had slightly longer kidneys than girls (both patients and controls), SRH was also noted more often in boys. The frequency of SRH was unrelated to age at nephrectomy, side of the solitary kidney, tumor stage, chemotherapy regimen, or treatment with radiation therapy.


CONCLUSIONS
Although renal growth in a solitary kidney is accelerated in most children after unilateral nephrectomy for Wilms' tumor, the sonographic length of the solitary kidney will be larger than normal in only half of the patients.
Zerin
J M
JM
Department of Radiology, James Whitcomb Riley Hospital for Children, Indiana University Medical Center, Indianapolis, IN 46209, USA.
Haliloglu
M
M
Cohen
M D
MD
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006984:Hypertrophy / Q000000981:diagnostic imaging; D007668:Kidney / Q000000981:diagnostic imaging / Q000473:pathology*; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D009392:Nephrectomy; D012016:Reference Values; D012189:Retrospective Studies; D014463:Ultrasonography; D009396:Wilms Tumor / Q000000981:diagnostic imaging / Q000601:surgery*