Malignant tumours of the kidney: imaging strategy

Abstract

Primitive malignant renal tumours comprise 6% of all childhood cancers. Wilms tumour (WT) or nephroblastoma is the most frequent type accounting for more than 90%. Imaging alone cannot differentiate between these tumours with certainty but it plays an important role in screening, diagnostic workup, assessment of therapy response, preoperative evaluation and follow-up. The outcome of WT after therapy is excellent with an overall survival around 90%. In tumours such as those where the outcome is extremely good, focus can be shifted to a risk-based stratification to maintain excellent outcome in children with low risk tumours while improving quality of life and decreasing toxicity and costs. This review will discuss the imaging issues for WT from the European perspective and briefly discuss the characteristics of other malignant renal tumours occurring in children and new imaging techniques with potential in this matter.

Fig. 1

Axial T2-W fat-supressed MR. 11-month-old boy with a right abdominal mass with a partially intrarenal localization (black arrow) and liver metastases. 123-Iodine-MIBG-scan was positive for neuroblastoma

Fig. 2

Axial T2-W fat-suppressed MR shows a large tumour with left renal origin. The mass was too large to be adequately imaged with US alone

Fig. 3

2.5-year-old girl with a left renal mass. US shows the kidney stretched around the tumour

Fig. 4

Twelve-year-old girl with Burkitt lymphoma. Coronal T2-W MR shows in addition to a large abdominal mass (partially shown, white arrows), multiple nodular lesions in both kidneys

Fig. 5

Two-year-old girl with bilateral nephroblastomatosis. a. Coronal T1-W MR after gadolinium administration shows multiple bilateral round lesions with different patterns of enhancement. b. Axial T2-W MR. The lesions show variable signal intensity. Some of the lesions eventually developed into WT

Fig. 6

Five-year-old girl with left sided WT. Abdominal US shows a large tumour thrombus in the IVC (white arrows)

Fig. 7

Nine-year-old girl with recurrence detected on routine US. She had been in complete remission over a 7 year period after a stage 2 intermediate risk WT. Courtesy of Dr. S. Robben

Fig. 8

Two-year-old girl with a clear cell sarcoma in the left kidney. Contrast-enhanced abdominal CT shows the mass indistinguishable from a WT on imaging studies