Wilms tumour
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Wilms tumour, also nephroblastoma and Wilms' tumour, is the most common pediatric kidney tumour.
General
- Common abdominal pediatric tumour.
- May be associated with a syndrome:[1]
- WAGR syndrome (Wilms tumour, Aniridia (absence of iris), GU abnormalities, Retardation).[2]
- Beckwith-Wiedemann syndrome.[3]
- Denys-Drash syndrome.[4]
Gross
- Lobulated tan mass.
Image: Wilms tumour (med.utah.edu).
Microscopic
Features - classically three components (blastema, immature stroma, tubules):[5]
- Malignant small round blue cells ("blastema"):
- 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.
- Stroma ("immature stroma"):
- Spindle cells:
- Elliptical nuclear membrane.
- Abundant loose cytoplasm.
- Spindle cells:
- Tubular structures ("tubules"):
- Usually clustered.
- Vaguely resemble a glomerulus.
- 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.[6]
- +/-Heterologous elements (skeletal muscle, smooth muscle adipose tissue, cartilage).[7]
- Heterologous = doesn't normally belong there.[8]
DDx:
- Metanephric adenoma.
- Nephrogenic nests.
- Other small round cell tumours.
- Synovial sarcoma, biphasic - especially in adults.
Notes:
- Palisade = fence made of stakes driven into the ground.[9]
- Approximately 30-40% Wilms tumour cases have nephrogenic rests.[10]
- The three phases are also called blastemal, epithelial and stromal.[7]
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)
www:
Anaplasia
Subclassified as:[7]
- Focal anaplasia.
- Diffuse anaplasia.
Criteria (all of the following):[7]
- Atypical mitoses.
- Nuclear hyperchromasia.
- Nuclear size variation (of the tumour cells) > 3x.
IHC
- WT-1 +ve.
See also
References
- ↑ URL: http://emedicine.medscape.com/article/989398-overview. Accessed on: 9 March 2011.
- ↑ Online 'Mendelian Inheritance in Man' (OMIM) 194072
- ↑ Online 'Mendelian Inheritance in Man' (OMIM) 130650
- ↑ Online 'Mendelian Inheritance in Man' (OMIM) 194080
- ↑ 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.
- ↑ URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970416-8. Accessed on: 28 March 2011.
- ↑ 7.0 7.1 7.2 7.3 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.
- ↑ URL: http://www.biology-online.org/dictionary/Heterologous. Accessed on: 1 October 2011.
- ↑ URL: http://www.thefreedictionary.com/palisaded. Accessed on: 2 February 2011.
- ↑ 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.