Unusual sonographic features of ARPKD

Area of Science:

• Perinatology
• Pediatric Nephrology
• Medical Imaging

Background:

• Autosomal recessive polycystic kidney disease (ARPKD) is a severe genetic disorder affecting fetal kidney development.
• Typical sonographic findings in ARPKD include enlarged echogenic kidneys, often with loss of corticomedullary differentiation.
• Accurate prenatal diagnosis is crucial for managing potential complications like pulmonary hypoplasia.

Observation:

• A fetus at 34 weeks' gestation presented with enlarged kidneys exhibiting pyramidal hyperechogenicity, resembling medullary nephrocalcinosis.
• The fetus was delivered at 39 weeks and succumbed within 22 hours due to pulmonary insufficiency secondary to severe oligohydramnios.
• Pathological examination revealed typical ARPKD with diffuse tubular dilatation and prominent fetal renal lobulation.

Findings:

• The sonographic finding of pyramidal hyperechogenicity in the fetal kidneys was a key observation.
• Post-mortem pathological analysis confirmed the diagnosis of ARPKD, correlating the gross and microscopic findings with the sonographic appearance.
• The prominent delineation of pyramids within lobules on section explained the observed sonographic pattern.

Implications:

• This case expands the spectrum of sonographic presentations of ARPKD in utero.
• Recognizing atypical sonographic findings is vital for accurate prenatal diagnosis and counseling.
• Understanding the pathological basis of imaging findings improves diagnostic precision in fetal medicine.