Wilms tumour

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Wilms tumour
Diagnosis in short

Wilms tumour. H&E stain.
Synonyms nephroblastoma
LM DDx metanephric adenoma, nephrogenic nests, small round cell tumours, Immature teratoma
IHC WT-1 +ve, CD56 +ve
Site kidney - see pediatric kidney tumours
Syndromes WAGR syndrome, Beckwith-Wiedemann syndrome, Denys-Drash syndrome
Signs +/-abdominal mass
Prevalence most common pediatric kidney tumour

Wilms tumour, also nephroblastoma and Wilms' tumour, is the most common pediatric kidney tumour.[1][2]

General

  • Common abdominal pediatric tumour.
    • Affects approximately 1 in 8000 children.
    • There is no sex predilection and the mean patient age at diagnosis ranges among 37 to 43 months.
  • May be associated with a syndrome:[3]

Gross

Features [7]

  • Most nephroblastomas are unifocal.
    • Usually solitary, rounded, multilobular masses sharply demarcated from adjacent parenchyma.
    • The cut surface is most commonly pale grey or tan.
    • Cyst most be prominent in some cases.
  • Multifocal masses in a single kidney and bilateral primary lesions are less frequent.

Images

  • Wilms tumour. (WC/AFIP)

www:

Microscopic

Features - classically three components (blastema, immature stroma, tubules):[8]

  1. Malignant small round blue cells ("blastema"):
    • The blastemal component is the least differentiated cellular element.
    • Size = ~ 2x RBC diameter.
    • Nuclear pleomorphism (variation of size, shape and staining).
      • Irregular nuclear membrane - important.
    • Scant/difficult to discern cytoplasm - basophilic (light blue).
    • Mitoses - common.
  2. Stroma ("immature stroma"):
    • Spindle cells:
      • Elliptical nuclear membrane.
      • Abundant loose cytoplasm.
  3. Epithelial components ("tubules"):
    • Primitive rossete-like tubules, well-formed maturing and mature tubules, glomerular structures and variably papillary architecture.
      • Usually clustered.
      • Usu. have a central (clear/white) space surrounded by a rim of intensely eosinophilic cytoplasm.
      • Nuclei of tubular structures often elongated and palisaded.

Other findings:

  • Commonly seen in association with nephrogenic rests.
    • Cluster of cells small (blue) cells; lack nuclear atypia seen in Wilms tumour.[9]
  • +/-Heterologous elements (skeletal muscle, smooth muscle adipose tissue, cartilage).[10]
    • Heterologous = doesn't normally belong there.[11]

DDx:

Notes:

  • Palisade = fence made of stakes driven into the ground.[12]
  • Approximately 30-40% Wilms tumour cases have nephrogenic rests.[13]
  • The three phases are also called blastemal, epithelial and stromal.[10]

Images

  • Wilms tumour - low mag. (WC/Nephron)

  • Wilms tumour - intermed. mag. (WC/Nephron)

  • Wilms tumour - high mag. (WC/Nephron)

  • Wilms tumour - very high mag. (WC/Nephron)

  • Wilms tumor - low mag. (WC/Ed Uthman)

www:

Anaplasia

Subclassified as:[10]

  1. Focal anaplasia.
  2. Diffuse anaplasia.

Criteria (all of the following):[10]

  1. Atypical mitoses.
  2. Nuclear hyperchromasia.
  3. Nuclear size variation (of the tumour cells) > 3x.

IHC

Molecular

  • Cytogenetics[15]
    • Partial gains of 1q.
    • Partial losses of 1p, 1q, 4q, 11q, 16q, 22q.
    • Complete loss of chromosome 16, 11, 12, 22.
    • Trisomy of chromosome 8, 12, 13, 18.

See also

References

  1. ↑ Coppes MJ, Wolff JE, Ritchey ML (1999). "Wilms tumour: diagnosis and treatment". Paediatr Drugs 1 (4): 251–62. PMID 10935424.
  2. ↑ Stefanowicz J, Sierota D, Balcerska A, Stoba C (2004). "[Wilms' tumour of unfavorable histology--results of treatment with the SIOP 93-01 protocol at the Gdańsk centre. Preliminary report]" (in Polish). Med Wieku Rozwoj 8 (2 Pt 1): 197–200. PMID 15738594.
  3. ↑ URL: http://emedicine.medscape.com/article/989398-overview. Accessed on: 9 March 2011.
  4. ↑ Online 'Mendelian Inheritance in Man' (OMIM) 194072
  5. ↑ Online 'Mendelian Inheritance in Man' (OMIM) 130650
  6. ↑ Online 'Mendelian Inheritance in Man' (OMIM) 194080
  7. ↑ Coppes, MJ.; Arnold, M.; Beckwith, JB.; Ritchey, ML.; D'Angio, GJ.; Green, DM.; Breslow, NE. (Apr 1999). "Factors affecting the risk of contralateral Wilms tumor development: a report from the National Wilms Tumor Study Group.". Cancer 85 (7): 1616-25. PMID 10193955.
  8. ↑ Mitchell, Richard; Kumar, Vinay; Fausto, Nelson; Abbas, Abul K.; Aster, Jon (2011). Pocket Companion to Robbins & Cotran Pathologic Basis of Disease (8th ed.). Elsevier Saunders. pp. 254-5. ISBN 978-1416054542.
  9. ↑ URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970416-8. Accessed on: 28 March 2011.
  10. ↑ 10.0 10.1 10.2 10.3 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 282. ISBN 978-0781765275.
  11. ↑ URL: http://www.biology-online.org/dictionary/Heterologous. Accessed on: 1 October 2011.
  12. ↑ URL: http://www.thefreedictionary.com/palisaded. Accessed on: 2 February 2011.
  13. ↑ Coppes MJ, Haber DA, Grundy PE (September 1994). "Genetic events in the development of Wilms' tumor". N. Engl. J. Med. 331 (9): 586–90. doi:10.1056/NEJM199409013310906. PMID 8047084.
  14. ↑ Muir, TE.; Cheville, JC.; Lager, DJ. (Oct 2001). "Metanephric adenoma, nephrogenic rests, and Wilms' tumor: a histologic and immunophenotypic comparison.". Am J Surg Pathol 25 (10): 1290-6. PMID 11688464.
  15. ↑ Md Zin, R.; Murch, A.; Charles, A. (Jun 2011). "Pathology, genetics and cytogenetics of Wilms' tumour.". Pathology 43 (4): 302-12. doi:10.1097/PAT.0b013e3283463575. PMID 21516053.
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