Presentation
Runny nose, cough, fever, eye discharge. Enlarged, rigid liver palpated on physical exam.
Patient Data
The liver is moderately enlarged and shows a coarsely heterogeneous echotexture, with a periportal predominance of hypoechoic areas.
The kidneys are substantially enlarged, with extensive areas of markedly echogenic confluent foci, both parenchymal and cortical, most likely representing innumerable tiny cysts.
Spleen length borderline for patient's age.
Impression: findings of polycystic kidneys and liver fibrosis, compatible with ARPKD.
Referred to CT the next day - "hyperechoic kidneys, hepatomegaly - malignancy?"
Enlarged liver with patchy hypodense areas in both lobes, best appreciated on the non-contrast scan, likely representing fibrosis.
Enlarged kidneys with hypodense areas corresponding to the clusters of microcysts seen on the ultrasound exam. In the renal excretory phase, both kidneys show mildly dilated collecting systems and thin radial stripes of contrast material, the latter likely representing dilated tubules.
Summary: findings support the diagnosis of ARPKD.
Case Discussion
ARPKD was suspected by the radiologist reporting the CT, but rather on the basis of the ultrasound findings of nephromegaly with innumerable microcysts plus a large, coarsely heterogeneous liver. When renal cysts are so tiny that each acts as a focal interface that bounces sound back to the transducer, they appear hyperechoic rather than anechoic. The CT study added the presence of dilated renal tubules and not much else.
Although the signs on the ultrasound study were pathognomonic for ARPKD, as well as lack of any clinical or radiological sign of a lysosomal/glycogen storage disease, genetic testing was performed nonetheless and confirmed ARPKD.