Pediatric kidney tumours
This article cover pediatric kidney tumours. Adult kidney tumour are covered in kidney tumours article. An introduction to pediatric pathology is in the pediatric pathology article.
Overview
These are diagnoses pediatric pathologists make.
The most common ones are:
Other renal tumours (not covered in this article):
- Postneuroblastoma RCC.
- Neuroblastoma.
- PNET.
- Synovial sarcoma.
- Lymphoma.
The translocation carcinomas are covered in the kidney tumours article
Specific tumours
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, 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:
- 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.
- Indistinct cell borders/cytoplasm; clear background.
- No nucleoli.
Images:
Renal rhabdoid tumour
- AKA rhabdoid tumour of the kidney, abbreviated RTK.
General
- Similar to extrarenal malignant rhabdoid tumour.[13]
- Arises from renal medulla.
- May be associated with a CNS tumour.
Microscopic
- Variable architecture.
- Round cells.
- Abundant cytoplasm with eosinophilic inclusions.
- Eccentric vesicular nucleus.
- Prominent nucleolus -- key feature.
Images:
IHC
- INI1 -ve.
Renal cell carcinoma
General
- Similar to in adults.
- Clear cell RCC not common - a tumour with the clear cell histomorphology is more often a renal tumour with Xp11.2 translocation.
Papillary RCC
- Most common form of RCC in children.
Clear cell RCC
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 13.4 13.5 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.
- ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 627. ISBN 978-0781765275.