A rare cause of echogenic kidneys with oligohydramnios in the fetus: report of two different cases.

Background: Prenatal ultrasound findings of fetal bilateral echogenic kidneys accompanied by oligohydramnios can be highly stressful for both pregnant women and physicians. The diversity of underlying causes makes it challenging to confirm a prenatal diagnosis, predict postnatal outcomes, and counsel regarding recurrence risks in future pregnancies.

Case presentation: We report two cases of abnormal fetal echogenic kidneys with oligohydramnios detected in the early third trimester. Autosomal recessive polycystic kidney disease (ARPKD), a rare genetic syndrome, was initially suspected in both cases. However, postnatal diagnoses differed: the first case was confirmed as glomerulocystic kidney disease (GCKD) through renal pathology, while the second case was diagnosed as ARPKD with a compound heterozygous likely pathogenic PKHD1 mutation.

Conclusion: Prenatal diagnosis of fetal echogenic kidneys with oligohydramnios should prioritize accurate diagnosis. Given the differences in the clinical spectrum, GCKD should be considered a differential diagnosis for this condition, particularly ARPKD. This study highlights the importance and benefits of molecular diagnosis and postnatal renal pathology for precise diagnosis and effective counseling.