Imaging of nephroblastomatosis: an overview.

Abstract

Nephroblastomatosis is an abnormality of nephrogenesis characterized by incomplete maturation of primitive nephrogenic cells. The resultant individual lesions have variable histologic findings and distribution in the kidney. There is wide acceptance of nephroblastomatosis as a precursor lesion to Wilms tumor. Consequently, the role of imaging in assessing patients for neoplastic transformation of nephroblastomatosis should be emphasized. Computed tomography (CT) has been shown to be superior to ultrasound (US) in this regard. Nonetheless, the low cost and lack of radiation of US make it attractive for serial screening studies. Although magnetic resonance imaging shows promise in assessment of the kidney for nephrogenic rests, experience is limited in its use in evaluating patients for nephroblastomatosis. The authors present protocols for assessing patients identified as being at either high or low risk for the development of Wilms tumor due to nephroblastomatosis. These protocols take into account the advantages of CT and US. Scanning intervals are determined from epidemiologic data on the occurrence of Wilms tumor; the most intense screening occurs during the younger ages of life, when the likelihood of Wilms tumor development is highest.

Bilateral Synchronous Wilms' Tumors in Nephroblastomatosis with Late Recurrence

“…Contrast-enhanced CT and MR images of NR demonstrate homogeneous hypodense/hypointense areas, whereas WT show inhomogeneous areas with variable attenuation/intensity (Figures 1, 2). [8][9][10] In our patient, the recurrent WTs appeared hypodense but also homogeneous on CT, more in agreement with NR ( Figure 3).…”

“…On ultrasound, the diffuse type is most often hypoechoic and the multifocal type often isoechoic to the renal cortex. 8,9 On CT and MRI, both types appear similar to renal cortex on non-enhanced scans. After contrast administration, NR become markedly hypodense on CT and hypointense on MRI in comparison with the intensely enhancing cortex (Figure 1, 2).…”

“…After contrast administration, NR become markedly hypodense on CT and hypointense on MRI in comparison with the intensely enhancing cortex (Figure 1, 2). [8][9][10] The more focal type of NR is not easily separated radiologically from renal lymphoma which is also frequently bilateral, and sometimes can be primary in the kidneys. The solid nature of the lesions excludes polycystic kidney disease.…”

“…It is recommended to follow such patients with imaging on a regular and frequent basis for 10 years to check for the possible development of new Wilms' tumors. 1,9,16 …”

Cystic renal mass in a patient with previous Wilm's tumour

“…In the multifocal form of nephroblastomatosis, areas of non-enhancing renal parenchyma are evident on contrast-enhanced CT, although renal enlargement is not usually a feature unless there is a concurrent Wilm's tumour [6]. Renal tuberculosis is usually unilateral and results in pericalyceal cyst formation, thickening and irregularity of the urothelium, debris within the collecting system and diffuse amorphous calcification.…”