Pediatric kidney tumours
This article cover pediatric kidney tumours. Adult kidney tumour are covered in kidney tumours article.
Wilms tumour
- AKA nephroblastoma, AKA Wilms' 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 - esp. 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:
- Nephrogenic rests (biologydisease.com).
- Wilms tumour (webpathology.com).
- Wilms tumour - low mag. (WC).
- Wilms tumour - very high mag. (WC).
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.
Metanephric stromal tumour
- Abbreviated MST.
General
- Infants and children.
- Diagnosed as mesoblastic nephroma in the past.[11]
- Benign and rare.[12]
Gross
Features:[11]
- Usu. renal medulla.
- Solid or cystic.
Microscopic
Features:[11]
- "Collarettes" - tumour cells surround blood vessels or renal tubules.
- Spindle cells/stellate cells.
- Variable cellular density - imparts a nodular appearance at low power.
- Indistinct cell borders/cytoplasm.
- Induces epithelioid morphology in smooth muscle cells.
Notes:
- +/-Heterologous elements.
DDx:
- Clear cell sarcoma of the kidney.[12]
- Mesoblastic nephroma.
Images:
Metanephric adenofibroma
General
- Adults and children.
Microsopic
Features:[11]
- Has features of:
- Stromal component.
- Similar to metanephric stromal tumour.
- Epithelial nodules.
- Similar to metanephric adenoma.
- Stromal component.
Mesoblastic nephroma
General
- Almost exclusively in infants.
Subclassified:
- Classic.
- Cellular.
- Mixed.
Gross
- Renal sinus infiltration - common.
Microscopic
Classic
Features:[13]
- Spindle cells in fascicles.
- Infiltrative border.
Cellular
Features:[13]
- Plump cells with vesicular nuclei.
- Well-defined border.
- Mitotically active.
Mixed
- Like the name implies - both classic pattern and cellular pattern areas are present.[13]
Molecular
Cellular mesoblastic nephroma:
- t(12:15)(p13;q25) ETV6/NTRK3.
- Same translocation if found in infantile fibrosarcoma.
Clear cell sarcoma of the kidney
- Not to be confused with clear cell sarcoma.
General
- Common pediatric renal tumour - second only to Wilms tumour.
- Aggressive.
Gross
- Renal medulla.
- +/-Cystic.
Microscopic
Features:[13]
- Polygonal cells/Stellate cells.
- Clear cytoplasm.
- No nucleoli.
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.
- ↑ 11.0 11.1 11.2 11.3 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 283. ISBN 978-0781765275.
- ↑ 12.0 12.1 Palese, MA.; Ferrer, F.; Perlman, E.; Gearhart, JP. (Sep 2001). "Metanephric stromal tumor: a rare benign pediatric renal mass.". Urology 58 (3): 462. PMID 11549506.
- ↑ 13.0 13.1 13.2 13.3 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 284. ISBN 978-0781765275.