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Joseph Junewick, MD FACR
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Nephrogenic Rest

Case Detail

Anatomy: Genitourinary
Joseph Junewick, MD FACR
Diagnostic Category: Neoplasia Benign
Created: over 3 years ago
Updated: over 3 years ago
Tags: PEDS
Modality/Study Types: US CT
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5 day old male with weight loss, hematuria and hyponatremia.

Case Images


Nephrogenic rest


US – Large poorly delineated hyper echoic central right renal lesion with occasional cystic spaces.

Non contrast CT – Noncalcified isodense right renal mass.

Contrast enhanced CT – Hypoenhancing central right renal mass.


Nephrogenic rests are persistent embryonic tissue related to incomplete induction of metanephric blastema by the ureteral bud
-Found in 1% of neonates although frequency rapidly decreases with age
-Lobar has greater malignant potential
-Perilobar is more common, (11p15)

Nephrogenic rests are present in 33% of kidneys with Wilms tumor

Syndromes associated with nephrogenic rests include
-Beckwith-Wiedemann syndrome (perilobar)
-Hemihypertrophy (perilobar)
-Sporadic aniridia (intralobar)
-Drash (intralobar)

Keys to differentiating nephrogenic rests from Wilms tumor
-Spherical shape Wilms
-Ovoid or lentiform nephrogenic rest
-greater than 3 cm Wilms
-less than 2 cm nephrogenic rest
-Fibrous capsule Wilms
-No capsule nephrogenic rest
-Heterogeneous texture Wilms
-Uniform texture nephrogenic rest


Lonergan GJ, Martinez-Leon MI, Agrons GA et al. Nephrogenic rests, nephroblastomatosis, and associated lesions of the kidney. Radiographics (1998); 18:947-968.

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