Case study

Renal block

Dr Willie ConradieMay 2012

Diagnostic Radiology

4yr old boy from Lesotho

O Weight lossO Normal “Mile-stones”O No chronic disease

O Resp: No coughing. No TB historyO GIT: No nausea/vomiting/diarhoea.O Uro: Normal frequency and colour

O Exam: Right sided abdominal mass..

Nephroblastomavs

Neuroblastoma?

Nephroblastoma(Wilms’ tumor)

O IncidenceO Most common malignant abdominal

neoplasm in children (1-8 years)

O 3rd most common malignancy in children

O LeukemiaO CNS tumors

O 3rd most common renal mass in children

O HydronephrosisO Multi-cystic dysplastic kidney

O 7% of all childhood Ca

Wilms tumor

O Familial in 1-2%O M=FO More common in blacks

O Peak age at 3-4 yearsO 90% before 8 yearsO Rare in neonates and adults

O Undifferentiated metanephric blastema (persistant primitive renal parenchyma)

O “nephrogenic rests”O Multiple foci = Nephroblastomatosis

O Genetic:O Abnormal WT1 (11p13) - WAGR/DRASHO Abnormal WT2 (11p15) - Beckwith-Wiedemann

- Hemihypertrophy

Rule of 10’s:

• 10% unfavourable histology• 10% bilateral• 10% vascular invasion• 10% calcifications• 10% pulmonary metastases at

presentation• 10% metastasize to liver

O CTO Poorly enhancing massO Well-defined margins or pseudocapsuleO Local extension into perirenal fat and local lymph

nodes

Wilms tumor

Best diagnostic clue:• Large heterogeneous mass• Replacing/in kidney• Displacement of organs/vessels• Extending into renal vein and IVC• Calcifications less often seen

Wilms tumor

O MR FindingsO TlWl: Typically low signal intensity on TlO T2Wl: High signal on T2

O heterogeneous andO frequently containing blood products

O MRA: useful in determining vascular spread pre-operatively

O Nuclear medicineO Bone Scan:

O Metastatic disease to bone occurs very late;O Not routine

O PETO Increasing use in Wilms and all pediatric tumorsO Primarily has an adjunctive, problem solving role

O Differentiating scar tissue from residual active tumor

NeuroblastomaO Incidence

O 3rd most common malignant tumor in infancy O LeukemiaO CNS

O Most common tumor in first week of life

O Most common solid, extra-cranial malignant tumor in children

O 8-10% of all childhood Ca

O 15 % of cancer deaths in children

Neuroblastoma

O Mean age at diagnosis = 22 monthsO 36% are infantsO 89% < 5yearsO 98% <10 years

O M:V = 1.1:1

O Malignant tumor of primitive neural crest cellsO Location

O Adrenal glands/para-vertebral sympathetic ganglia (70%)

O Posterior mediastinum (20%)O Pelvis (2-5%)O Neck (1-5%)

O MRIO High on T2WI; Low on T1WI O Heterogeneous - related to calcification/hemorrhage/necrosisO Excellent for detecting extension of tumor into spinal canal.

Neuroblastoma

Best diagnostic clue:• Invasive heterogeneous suprarenal mass • Calcifications (85%)• Crosses midline• Rather surrounds and engulfs vasculature • Tendency to invade spinal canal (via

neuroforamina)• Metastasizes commonly to bone, liver and LN

Neuroblastoma

O Nuclear medicineO Bone Scan

O Technetium-99m MDPO Uptake seen in bony metastasis (both cortical and

marrow)O Calcified primary mass often also demonstrated

uptake (up to74% of cases)

O MIBGO Metaiodobenzylguanidine

O Avid uptake related to catecholamine productionO Excellent for following extent of disease in MIBG

avid tumorsO 30% of neuroblastoma are not MIBG avid

STAGE

• I- Limited to organ of origin• II- Regional spread not crossing midline• III- Extension across midline• IV- Metasteses• IVs- I or II with disease limited to liver, skin, BM

WITHOUT radiographic evidence of bone metasteses.

Neuroblastoma

References1. Siegel MJ, Chung EM. Wilms’ tumor and other

pediatric renal masses. Magn Reson Imaging Clin N Am 16 (2008):479-497.

2. Siegel MJ, AlokJaju. MR Imaging of Neuroblastic masses. Magn Reson Imaging Clin N Am 16 (2008):499-513.

3. Donnely et al. Diagnostic Imaging: Pediatrics. First edition. 5:50-53; 5:78-81.

4. Dahnert W. Radiology Review Manual. Sixth edition: 940-942; 992-993.