Nephroblastomatosis

  • Etiology:
    — Nephroblastoma is a nephrogenic rest = persistent focus of fetal metanephric blastema after cessation of nephrogenesis (34-36 weeks gestation) which most likely resolves spontaneously but which may transform into Wilms tumor
    — Nephroblastomatosis – multiple or diffuse nephrogenic rests
  • Imaging: Non-spherical lesion
  • Imaging US: Hypoechoic or isoechoic
  • Imaging CT: More sensitive than US, enhance less than normal cortex, diffuse form has hypoattenuating rind
  • Imaging MRI:
    — T1WI: Isointense to hypointense
    — T1WI post contrast: Enhance less than normal renal parenchyma with homogenous signal
    — T2WI: Isointense to hypointense, if hyperintense suspect Wilms tumor
  • DDX:
  • Complications: Malignant transformation
  • Treatment: Surgical
  • Clinical:
    — Seen in 1% of neonatal kidneys at autopsy
    — Seen in 30-40% of unilateral Wilms and seen in 94-99% of bilateral Wilms
    — Intralobar – Less common, more likely to undergo malignant transformation, associated conditions: 11p15 mutations – Sporadic aniridia, Denys-Drash syndrome, WAGR
    — Perilobar – Less likely to become malignant, associated conditions: 11p13 mutations – hemihypertrophy, Beckwith-Wiedemann syndrome, Perlman syndrome, Trisomy 18

Radiology Cases of Nephroblastomatosis

Radiology Cases of Wilms Tumor in Left Kidney and Nephroblastomatosis in Right Kidney

US and MRI of nephroblastomatosis
Sagittal (above left) and transverse (above right) US images of the left kidney show it to be enlarged and echogenic in appearance with little recognizable normal renal parenchyma. Axial T2 (lower left), T1 (lower middle) and T1 post contrast (lower right) MR images of the right kidney shows a small round lesion that is hyperintense on T2, isointense on T1, and that does not enhance after the administration of contrast. Two additional identical appearing lesions were seen in the right kidney.