Fetal pelvic kidney: a challenge in prenatal diagnosis?

Abstract

The objective of this study was to establish ultrasonographic guidelines for the prenatal diagnosis of fetal pelvic kidneys and assess the relationship to clinical outcome. The records of all ultrasonographic diagnoses of a fetal pelvic kidney between 1 January 1991 and 31 December 1993 were reviewed. After review of the sonographic evaluation, the prenatal records were obtained, to assess demographic data as well as the obstetric course and neonatal outcome. If a fetal pelvic kidney was suspected on prenatal ultrasound examination, its precise location and size were recorded and compared with neonatal sonograms. Twenty-six cases of fetal ectopic kidney were diagnosed of which 13 were on the right side and 13 on the left (24/26 cases were diagnosed in the late second trimester). The size of the ectopic kidney did not differ from that of the normal kidney. Except for one case of hydronephrosis, there were no associated structural anomalies. All prenatal diagnoses were confirmed by postnatal sonograms and all neonates had normal renal function. Our conclusions are that prenatal sonographic detection of fetal pelvic kidney is feasible, although in most cases the diagnosis is made beyond 24 weeks' gestation. The importance of prenatal diagnosis is that the parents can be reassured that normal renal function is highly probable and that early neonatal intervention is usually unnecessary.

Sonographic Findings of Fetuses with an Empty Renal Fossa and Normal Amniotic Fluid Volume

“…The prevalence of pelvic kidney is frequently quoted as 1 in 1,200 autopsies [9], although others postulate that this should be somewhat around 1 in 700 [10], as they are mostly asymptomatic. On the other hand the reported prevalence of fetal pelvic kidneys in previous series are 1 in 1,965 [11] and 1 in 1,112 fetuses [12]. We were not able to report the true incidence of renal agenesis and renal ectopia as well as the false negative rate of prenatal sonography in detecting these malformations, because routine sonographic examination of the urinary system in asymptomatic newborns is not part of our general health care system.…”

“…In their study, Hill et al classified pelvic kidneys according to their localization within the fetal pelvis either as ipsilateral or midline but did not describe the exact diagnostic criteria [11]. On the other hand, in reviewing their sonographic data, Meizner et al found that, in all cases with postnatally proven pelvic kidneys, these were located opposite the sacrum and below the aortic bifurcation [12]. Instead of using similar strict sonographic criteria, we have made the diagnosis of pelvic kidney if they were in close proximity to the fetal bladder ( fig.…”

Kidney, Urinary Bladder, and Ureter

“…Ureteral ectopia can be associated with imperforate anus and tracheoesophageal fistula (Cinman et al 2007). Prenatal diagnosis of pelvic kidney is available after 24 weeks of gestation (Meizner et al 1995). In men, associated genital abnormalities are seen in 10-20% of patients, including undescended testes, urethral duplication, and hypospadias (Kocak et al 2001).…”

Prenatal Diagnosis of Cross-Fused Renal Ectopia: Does Color Doppler and 3-Dimensional Sonography Help?

“…Cross‐fused renal ectopia is an uncommon congenital anomaly, with an estimated prevalence of 1 per 1000 to 7500 autopsies 2 – 4 . Prior (postnatal) retrospective case studies suggest a male predominance (3:2) and a greater left‐to‐right crossover frequency 1 , 2 , 5 , 6 . This anomaly is theorized to result from abnormal development of the ureteric bud and metanephric blastema during the fourth to eighth weeks of gestation 2 , 6 .…”

“…This anomaly is theorized to result from abnormal development of the ureteric bud and metanephric blastema during the fourth to eighth weeks of gestation 2 , 6 . Other theories regarding the etiology of cross‐fused renal ectopia include pressure from abnormally placed umbilical arteries, malrotation of the caudal end of the fetus, teratogenic factors, and genetic factors 5 , 6 …”