A Pediatric Radiology Textbook and Pediatric Radiology Digital Library
Wilms Tumor
Etiology: — Renal origin — 30% of unilateral and 100% of bilateral Wilms tumor are due to nephrogenic rests
Imaging screening: In hemihypertrophy and Beckwith Wiedemann syndrome – baseline at 6 months, get US every 3 months until 8 years old, lesion becoming larger or rounder suggests malignant degeneration
Imaging at presentation: — Establish the stage of tumor – local or locoregional or metastatic — Look for tumor rupture and ipsilateral or contralateral synchronous tumor and vascular invasion in renal vein and IVC — Chest CT for pulmonary metastatic disease — MRI superior for detecting bilateral renal disease
Imaging: — Well circumscribed, round, heterogenous, some cystic components, may contain small amounts of fat, fine calcifications in 9% — Enhance less than normal parenchyma — Venous invasion — Claw sign — Deforms the collecting system showing it is an intrarenal mass — Pushing tumor that displaces vessels — Multicentric in 10-15%
Complications: Regional spread to lymph nodes and renal vein and inferior vena cava and right atrium tumor thrombus, contralateral kidney – synchronous or metachronous in 10%, metastasis to lung and liver and bone in 12%
Treatment: Chemotherapy then surgical
Clinical: — Most common abdominal malignancy of childhood — 87% of kidney masses in children — Peak at 3 1/2 years — 80% less than 5 years — Rare in neonates — Palpable mass in 75-95% — Presents most commonly as palpable mass and infrequently with pain and hematuria and constitutional symptoms — Associated with Beckwith-Wiedemann syndrome (macroglossia, omphalocele, visceromegaly – liver and kidneys and pancreas, gigantism or hemihypertrophy or Wilms tumor in 10%) — Bilateral Wilms is virtually always genetic or syndrome associated
Radiology Cases of Wilms Tumor
Radiology Cases of Unilateral Wilms Tumor
Sagittal US of the left kidney (upper left) shows a round hyperechoic lesion in the lower pole of the kidney. Axial T2 MRI without contrast of the abdomen (upper right) and coronal T1 MRI without (lower left) and with (lower right) contrast of the abdomen shows a well-circumscribed, solid T1 hypointense and T2 isointense mass in the lower pole of the left kidney that enhances minimally.Axial (above right), coronal (below middle) and sagittal (below right) CT with contrast of the abdomen shows a large heterogenous non-calcified mass that fills the entire left side of the abdomen. The inferior vena cava (to the right of the aorta) was distended with tumor thrombus. Multiple liver (above left) and lung (below left) lesions are also seen.AXR (above left) shows displacement of the bowel out of the right side of the abdomen. Sagittal US of the right kidney (above right) shows a large right renal mass that spares the upper pole of the right kidney. Coronal T1 MRI with contrast of the abdomen (below left) shows a large mass that is heterogenous in appearance that arises from the lower pole of the right kidney and that is demonstrating a claw sign superiorly. Axial T2 MRI (below right) again shows the heterogenous nature of the mass due to hemorrhage and necrosis.Transverse (above) and sagittal (below) US of the kidney shows an oval mass-like lesion that has been stable over time in the posterior aspect of the upper pole of the kidney that is not in continuity with the cortex of the kidney and has the same echogenicity of the cortex of the remainder of the kidney. Mild to moderate hydronephrosis is also present.
Axial CT without contrast of the abdomen (above) show a large right renal mass with some coarse calcifications within it. Axial CT with contrast (middle and below) shows a low density mass to be arising from the hilum of the right kidney and to be approaching the midline. The inferior vena cava appears to be clear of tumor as does the left kidney.Axial CT with contrast of the abdomen (above) shows a large non-calcified and non-enhancing mass crossing the midline with multiple retrocrural lymph nodes present. Axial CT (below) shows the mass is arising from the upper pole of the right kidney. The right renal vein and inferior vena cava are not clearly seen.Axial CT without intravenous contrast but with oral contrast of the abdomen (above) shows a large right sided abdominal mass that is calcified. Axial CT with intravenous and oral contrast of the abdomen (below) shows the mass is heterogenous in appearance, does not cross the midline, and the normally enhancing right kidney is demonstrating a claw sign along its posterior aspect.
Radiology Cases of Bilateral Wilms Tumor
Axial (left) and coronal (right) CT with contrast of the abdomen shows a large rounded solid heterogenous mass arising from the upper pole of the right kidney and a large rounded solid heterogenous mass arising from the center of the left kidney.Axial CT with contrast of the abdomen shows a large oval low density lesion arising from the right kidney and causing a claw sign. There is also a second smaller round low density lesion arising from the posterior aspect of the left kidney.
Radiology Cases of Cystic Wilms Tumor
Axial (left) CT with contrast of the abdomen shows a large cystic mass with septations in the left side of the abdomen. Coronal immediate image (above right) shows a claw sign proving the left kidney is the organ of origin of the mass. Coronal delayed image (below right) shows the mass has a mural nodule superiorly within it.
Radiology Cases of Wilms Tumor in the Left Kidney and Nephroblastomatosis in the Right Kidney
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.
Radiology Cases of Lung Metastases in Wilms Tumor
CXR PA shows a large round opacity just lateral to the left pulmonary artery which is located anteriorly on the lateral view.CXR AP (above) shows a soft tissue density projecting in the right cardiophrenic angle. Axial CT with contrast of the chest (below) shows a soft tissue mass in the right posterior costophrenic sulcus.Axial (above right), coronal (below middle) and sagittal (below right) CT with contrast of the abdomen shows a large heterogenous non-calcified mass that fills the entire left side of the abdomen. The inferior vena cava (to the right of the aorta) was distended with tumor thrombus. Multiple liver (above left) and lung (below left) lesions are also seen.
Radiology Cases of Hepatic Metastases in Wilms Tumor
Axial (above right), coronal (below middle) and sagittal (below right) CT with contrast of the abdomen shows a large heterogenous non-calcified mass that fills the entire left side of the abdomen. The inferior vena cava (to the right of the aorta) was distended with tumor thrombus. Multiple liver (above left) and lung (below left) lesions are also seen.
Radiology Cases of Inferior Vena Cava Invasion in Wilms Tumor
Axial (above right), coronal (below middle) and sagittal (below right) CT with contrast of the abdomen shows a large heterogenous non-calcified mass that fills the entire left side of the abdomen. The inferior vena cava (to the right of the aorta) was distended with tumor thrombus. Multiple liver (above left) and lung (below left) lesions are also seen.
Radiology Cases of Complications of Treatment of Wilms Tumor
Radiology Cases of Complications of Treatment of Wilms Tumor – Radiation Induced Enteritis
AP image from an enema shows a fixed narrowing of the descending colon from the splenic flexure to the sigmoid colon with dilation of the colon proximal to it. The extremely dilated cecum is in the midline of the pelvis.
Clinical Cases of Wilms Tumor
Clinical image shows absence of the iris.
Surgical Cases of Wilms Tumor
Surgical image shows a large heterogenous mass in the right kidney (to the right of the surgical field) which was intimately adherent to the ileum and cecum (to the left of the surgical field).Surgical image shows a large mass arising from the left kidney which is being effectively transilluminated by the overhead lights, demonstrating its primarily cystic nature.Surgical image shows a large fluid-filled mass arising from the left kidney just after it has been resected along with the left ureter.
Gross Pathology Cases of Wilms Tumor
Gross pathological image shows a whitish-tan mass with areas of hemorrhage and necrosis arising from the lower pole of the kidney. Note the compression of the adjacent renal tissue which manifests itself on imaging as the renal “claw” sign.Gross pathological image after right nephroureterectomy and en bloc ileocolectomy shows a large heterogenous mass in the right kidney which was intimately adherent to the cecum (held by the forceps on the right) and the ileum (held by the forceps on the left).Sectioned gross pathological image shows a large, heterogenous, round mass arising from the inferior pole of the right kidney. Note the claw sign of the renal parenchyma draped along the lateral margin of the mass.Gross pathological image (left) shows a large, heterogenous mass arising from the inferior pole of the right kidney. Note the claw sign of the renal parenchyma draped along the medial and lateral margins of the mass on the sectioned gross pathological image (right).Gross pathological image shows a large left renal mass along with the left ureter with the upper part of the mass being ballotable, demonstrating its primarily cystic nature.Sectioned gross pathological image after drainage of fluid shows the preserved lower pole of the left kidney (above), the replacement of the upper and middle poles by a cystic tumor containing multiple septations which is now decompressed, and a mural nodule (center of image).Post-mortem gross pathological images obtained anteriorly (on the left) and posteriorly (on the right) show a mass in the upper pole of the right kidney. The upper pole of the left kidney is fused to the lower pole of the right kidney.
Histopathology Cases of Wilms Tumor
Histopathological image H&E stained section shows the classic triphasic histologic appearance of these lesions as they recapitulate normal nephrogenesis – stroma (spindle shaped cells), blastema (islands of undifferentiated small round blue cells) and epithelium (tubular / glandular structures); mitoses and necrosis are frequent with no adverse prognostic significance.
