eMedicine Specialties > Urology > Cancer, Wilms Tumor and Neuroblastoma

Wilms Tumor: Workup

Author: Marc Cendron, MD, Associate Professor of Surgery, Harvard School of Medicine; Consulting Staff, Department of Urological Surgery, Children's Hospital Boston
Contributor Information and Disclosures

Updated: May 5, 2009

Workup

Laboratory Studies

  • Complete blood count
  • Basic metabolic panel, including serum calcium levels
  • Coagulation abnormalities (to rule out acquired von Willebrand disease, which is coincident in up to 8% of individuals with Wilms tumor)
  • Liver function tests
  • Renal function tests
  • Urinalysis and urine culture

Imaging Studies

  • Ultrasonography
    • Initial diagnosis of a renal or abdominal mass, possible renal vein or inferior vena cava (IVC) thrombus (Doppler flow study may be helpful in the setting of vascular invasion.)
    • Information regarding liver and other kidney
  • CT scanning of the chest and abdomen
    • Differential diagnosis of a kidney tumor versus adrenal tumor (neuroblastoma)
    • Liver metastases
    • Status of opposite kidney
    • Lymph node assessment
    • Status of chest with respect to metastases
  • Chest radiography - As a baseline for pulmonary metastases
  • Bone scan - Necessary for children with clear cell sarcoma of the kidney
  • Magnetic resonance imaging
    • Typically, these tumors appear inhomogeneous on gadolinium-enhanced MRI, while the nephrogenic rests (which sometimes are precursors of Wilms tumor [WT]) appear as homogeneous masses.
    • MRI is also useful for magnetic resonance venography to aid in the diagnosis of thrombus of the renal vein of the IVC.
    • MRI scanning of the head is recommended in patients with suspected rhabdoid and clear cell carcinoma of the kidney.

Other Tests

  • Chromosomal analysis and gene mapping
  • Analysis for LOH on chromosomes 1p and 16q

Histologic Findings

Wilms tumor arises from the primitive embryonal renal tissue and contains epithelial, stromal, and blastemal elements.

Favorable histology (90% of cases) is characterized by all 3 histological elements, without any anaplastic features. The cure rate in these cases is close to 90%. Occasionally, foci of cartilaginous, adipose, or muscle tissue may appear (ie, teratoid Wilms tumor).

Unfavorable histology (10% of cases): Clear cell carcinoma of the kidney (bone-metastasizing renal tumor of childhood) and rhabdoid tumor of the kidney are now considered distinct type tumors and should not be included.

Anaplasia is defined by nuclear enlargement, nuclear hyperchromasia, and abnormal mitoses. Focal anaplasia is defined as less than 10% anaplastic features in a specimen, whereas more than 10% is considered diffuse anaplasia. Nephrogenic rests are foci of abnormally present nephrogenic renal blastemal cells (metanephric blastema). These are considered precursors of Wilms tumor. Nephroblastomatosis is the diffuse presence of nephrogenic rests. It may be perilobar; intralobar (usually the more primitive elements are situated intralobarly), which has been associated more frequently with the development of Wilms tumor than the perilobar blastemal rests; or panlobular.

Grossly, Wilms tumor is typically an intrarenal solid or cystic mass that displaces the collecting system. It usually has a pseudocapsule and may contain hemorrhage and necrosis. The tumor extends into the renal vein in 40% of cases. It rarely extends into the ureter and bladder.

The partially differentiated cystic nephroblastoma (ie, multilocular cystic nephroma) with possible Wilms elements is generally considered a benign lesion.

Staging

NWTSG recommends surgical staging in every case. In addition, recent data have suggested that patients with Wilms tumor undergo an individual risk assessment based on biological determinants or markers.

  • Stage I: The tumor is limited to the kidney and is excised completely.
  • Stage II: The tumor extends beyond the kidney but is excised completely. Capsular penetration, renal vein involvement, and renal sinus involvement may also be found. A biopsy of the tumor is performed, and local spillage occurs.
  • Stage III: Residual intra-abdominal tumor (nonhematogenous) exists after the completion of surgery. Lymph node findings are positive, or peritoneal implants are found. The resected specimen has histologically positive margins, or the tumor has been spilled into the abdominal cavity.
  • Stage IV: Hematogenous or lymph node metastasis has occurred outside the abdomen or pelvis.
  • Stage V: Synchronous bilateral involvement has occurred. Each side is assigned a stage from I to III, and histology is based on biopsy findings.

More on Wilms Tumor

Overview: Wilms Tumor
Workup: Wilms Tumor
Treatment: Wilms Tumor
Follow-up: Wilms Tumor
References
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References

  1. Coppes MJ, Egeler RM. Genetics of Wilms' tumor. Semin Urol Oncol. Feb 1999;17(1):2-10. [Medline].

  2. Davies-Johns T, Chidel M, Macklis RM. The role of radiation therapy in the management of Wilms' tumor. Semin Urol Oncol. Feb 1999;17(1):46-54. [Medline].

  3. de Kraker J, Jones KP. Treatment of Wilms tumor: an international perspective. J Clin Oncol. May 1 2005;23(13):3156-7; author reply 3157-8. [Medline].

  4. Egeler RM, Wolff JE, Anderson RA, Coppes MJ. Long-term complications and post-treatment follow-up of patients with Wilms' tumor. Semin Urol Oncol. Feb 1999;17(1):55-61. [Medline].

  5. Goske MJ, Mitchell C, Reslan WA. Imaging of patients with Wilms' tumor. Semin Urol Oncol. Feb 1999;17(1):11-20. [Medline].

  6. Green DM. The treatment of stages I-IV favorable histology Wilms' tumor. J Clin Oncol. Apr 15 2004;22(8):1366-72. [Medline].

  7. Levien MG, Bringelsen KA. Postoperative chemotherapy in the National Wilms' Tumor Studies. Semin Urol Oncol. Feb 1999;17(1):40-5. [Medline].

  8. Li W, Kessler P, Yeger H, Alami J, Reeve AE, Heathcott R. A gene expression signature for relapse of primary wilms tumors. Cancer Res. Apr 1 2005;65(7):2592-601. [Medline].

  9. Metzger ML, Dome JS. Current therapy for Wilms' tumor. Oncologist. Nov-Dec 2005;10(10):815-26. [Medline].

  10. Ritchey ML. The role of preoperative chemotherapy for Wilms' tumor: the NWTSG perspective. National Wilms' Tumor Study Group. Semin Urol Oncol. Feb 1999;17(1):21-7. [Medline].

  11. Ross JH, Kay R. Surgical considerations for patients with Wilms' tumor. Semin Urol Oncol. Feb 1999;17(1):33-9. [Medline].

  12. Vujanic GM, Sandstedt B, Harms D, Kelsey A, Leuschner I, de Kraker J. Revised International Society of Paediatric Oncology (SIOP) working classification of renal tumors of childhood. Med Pediatr Oncol. Feb 2002;38(2):79-82. [Medline].

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Further Reading

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Keywords

Wilms tumor, nephroblastoma, WT, embryoma of the kidney, mixed tumor of the kidney, sporadic Wilms tumor, familial Wilms tumor, bilateral Wilms tumor, Beckwith-Wiedemann syndrome, hemihypertrophy, congenital aniridia, WAGR syndrome, Denys-Drash syndrome, trisomy 18 mutation, teratoid Wilms tumor

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Contributor Information and Disclosures

Author

Marc Cendron, MD, Associate Professor of Surgery, Harvard School of Medicine; Consulting Staff, Department of Urological Surgery, Children's Hospital Boston
Marc Cendron, MD is a member of the following medical societies: American Academy of Pediatrics, American Urological Association, European Society for Paediatric Urology, Johns Hopkins Medical and Surgical Association, New Hampshire Medical Society, Society for Fetal Urology, and Society for Pediatric Urology
Disclosure: Nothing to disclose.

Medical Editor

Leonard Gabriel Gomella, MD, FACS, The Bernard W Godwin Professor of Prostate Cancer Chairman, Department of Urology, Associate Director of Clinical Affairs, Kimmel Cancer Center, Thomas Jefferson University
Leonard Gabriel Gomella, MD, FACS is a member of the following medical societies: American Association for Cancer Research, American College of Surgeons, American Medical Association, American Society for Laser Medicine and Surgery, American Urological Association, Sigma Xi, Society for Basic Urologic Research, Society of University Urologists, and Society of Urologic Oncology
Disclosure: GSK Consulting fee Consulting; Astra Zeneca Honoraria Speaking and teaching; Watson Pharmaceuticals Consulting fee Consulting

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Dan Theodorescu, MD, PhD, Paul Mellon Professor of Urologic Oncology, Department of Urology, University of Virginia Health Sciences Center
Dan Theodorescu, MD, PhD is a member of the following medical societies: American Cancer Society, American College of Surgeons, American Urological Association, Medical Society of Virginia, Society for Basic Urologic Research, and Society of Urologic Oncology
Disclosure: Nothing to disclose.

CME Editor

J Stuart Wolf Jr, MD, FACS, David A Bloom Professor of Urology, Director of Division of Minimally Invasive Urology, Department of Urology, University of Michigan
J Stuart Wolf Jr, MD, FACS is a member of the following medical societies: American College of Surgeons, American Urological Association, Catholic Medical Association, Endourological Society, Society for Urology and Engineering, Society of Laparoendoscopic Surgeons, Society of University Urologists, and Society of Urologic Oncology
Disclosure: Terumo Corporation Consulting fee Consulting; Omeros Corporation Consulting fee Consulting

Chief Editor

Bradley Fields Schwartz, DO, FACS, Professor of Urology, Director, Center for Laparoscopy and Endourology, Department of Surgery, Southern Illinois University School of Medicine
Bradley Fields Schwartz, DO, FACS is a member of the following medical societies: American College of Surgeons, American Urological Association, Association of Military Osteopathic Physicians and Surgeons, Endourological Society, Society of Laparoendoscopic Surgeons, and Society of University Urologists
Disclosure: Nothing to disclose.

 
 
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