Medulloblastoma

Medulloblastoma is a malignant small round cell tumour that is found in the cerebellum.

Morphologically identical supratentorial tumours are called primitive neuroectodermal tumour (PNET).

General

Mostly paediatric population.
May be seen as a component of nevoid basal cell carcinoma syndrome (NBCCS).
- Gene: patched (abbreviated PTCH1).^[1]
Commonly spread via cerebrospinal fluid (CSF).^[2]
- May be detected in CSF cytopathology specimens.

Gross

Location: cerebellum - key feature.
- Morphologically identical supratentorial tumours are called primitive neuroectodermal tumour (PNET).
- Supratentorial and spinal metastases from initial tumor possible.

Microscopic

Features:^[3]

Small round cell tumour.
Homer-Wright rosettes:
- Rosette with a meshwork of fibers (neuropil) at the centre.^[4]

IHC

MAP2 usu. +ve
Synaptophysin +ve (weak to strong)
NSE +ve/-ve
NF +ve/-ve
Chromogranin +ve/-ve
GFAP +ve/-ve (mostly along blood vessels)
Vimentin +ve
Nestin +ve
INI1 retained (no loss)

DDx:

Small round cell tumours.
- AT/RT (INI1 loss)
- CNS-PNET
- ETMR (LIN28)-positive
- Ewing Sarcoma family members
- Small cell glioblastoma

Images

Medulloblastoma. (WC/KGH)
Medulloblastoma. (WC/KGH)
Homer-Wright rosettes in a medulloblastoma. (WC/jensflorian)
Cerebellar infiltrative growth. (WC/jensflorian)
Demsomplastic nodular medullloblastoma. (WC/jensflorian)
Anaplastic large cell medulloblastoma. (WC/jensflorian)
Medulloblastoma cells smear. (AFIP)
Medulloblastoma in the cerebellum. (AFIP)
Reticulin stain highlighting "pale islands" in a desmoplastic medulloblastoma (WC/jensflorian)
MIB-1 immunostaining in desmoplastic medulloblastoma (WC/jensflorian)

Case:

Classic Medulloblastoma of the SHH type. (WC/jensflorian)
Epitheloid ribboning and nuclear moulding of tumor cells. (WC/jensflorian)
Areas of geographic necrosis. (WC/jensflorian)
Partial MAP2 immunoreactivity. (WC/jensflorian)

www:

Subtypes

Histologically defined

Classic medulloblastoma (~85% of all medulloblastomas).
Variants of medulloblastoma (~15% of all medulloblastomas together):
1. Anaplastic / Large cell variant.
2. Desmoplastic/nodular medulloblastoma (DNMB).
3. Medulloblastoma with extensive nodularity (MBEN).

Anaplastic variant

Features:

Larger cells.
Severe anaplasia.
Polygonal cells.

Genetically defined

WNT
SHH
- infantile and adult cases are biologically different, esp p53 mutant tumors are associated with poor outcome.^[5]
Group 3
Group 4

Prognosis

Prognosis based on histology:^[6]^[7]^[8] DNMB & MBEN > classic > anaplastic & large cell variant.
Prognosis based on genetics:^[9] WNT > SHH (without Tp53 mut) > Group 4 > Group 3 > SHH (with Tp53 mut).

References

↑ Online 'Mendelian Inheritance in Man' (OMIM) 601309
↑ Lefkowitch, Jay H. (2006). Anatomic Pathology Board Review (1st ed.). Saunders. pp. 424 Q34. ISBN 978-1416025887.
↑ URL: http://moon.ouhsc.edu/kfung/jty1/neurotest/Q93-Ans.htm. Accessed on: 26 October 2010.
↑ Wippold FJ, Perry A (March 2006). "Neuropathology for the neuroradiologist: rosettes and pseudorosettes". AJNR Am J Neuroradiol 27 (3): 488–92. PMID 16551982.
↑ Kool, M.; Jones, DT.; Jäger, N.; Northcott, PA.; Pugh, TJ.; Hovestadt, V.; Piro, RM.; Esparza, LA. et al. (Mar 2014). "Genome sequencing of SHH medulloblastoma predicts genotype-related response to smoothened inhibition.". Cancer Cell 25 (3): 393-405. doi:10.1016/j.ccr.2014.02.004. PMID 24651015.
↑ Gulino A, Arcella A, Giangaspero F (November 2008). "Pathological and molecular heterogeneity of medulloblastoma". Curr Opin Oncol 20 (6): 668–75. doi:10.1097/CCO.0b013e32831369f4. PMID 18841049.
↑ Rutkowski S, von Hoff K, Emser A, et al. (November 2010). "Survival and Prognostic Factors of Early Childhood Medulloblastoma: An International Meta-Analysis". J Clin Oncol 28 (33): 4961–4968. doi:10.1200/JCO.2010.30.2299. PMID 20940197.
↑ Rutkowski, S.; Bode, U.; Deinlein, F.; Ottensmeier, H.; Warmuth-Metz, M.; Soerensen, N.; Graf, N.; Emser, A. et al. (Mar 2005). "Treatment of early childhood medulloblastoma by postoperative chemotherapy alone.". N Engl J Med 352 (10): 978-86. doi:10.1056/NEJMoa042176. PMID 15758008.
↑ Ramaswamy, V.; Remke, M.; Bouffet, E.; Bailey, S.; Clifford, SC.; Doz, F.; Kool, M.; Dufour, C. et al. (Jun 2016). "Risk stratification of childhood medulloblastoma in the molecular era: the current consensus.". Acta Neuropathol 131 (6): 821-31. doi:10.1007/s00401-016-1569-6. PMID 27040285.

[omim601309-1] Online 'Mendelian Inheritance in Man' (OMIM) 601309

[2] Lefkowitch, Jay H. (2006). Anatomic Pathology Board Review (1st ed.). Saunders. pp. 424 Q34. ISBN 978-1416025887.

[3] URL: http://moon.ouhsc.edu/kfung/jty1/neurotest/Q93-Ans.htm. Accessed on: 26 October 2010.

[4] Wippold FJ, Perry A (March 2006). "Neuropathology for the neuroradiologist: rosettes and pseudorosettes". AJNR Am J Neuroradiol 27 (3): 488–92. PMID 16551982.

[5] Kool, M.; Jones, DT.; Jäger, N.; Northcott, PA.; Pugh, TJ.; Hovestadt, V.; Piro, RM.; Esparza, LA. et al. (Mar 2014). "Genome sequencing of SHH medulloblastoma predicts genotype-related response to smoothened inhibition.". Cancer Cell 25 (3): 393-405. doi:10.1016/j.ccr.2014.02.004. PMID 24651015.

[pmid18841049-6] Gulino A, Arcella A, Giangaspero F (November 2008). "Pathological and molecular heterogeneity of medulloblastoma". Curr Opin Oncol 20 (6): 668–75. doi:10.1097/CCO.0b013e32831369f4. PMID 18841049.

[pmid20940197-7] Rutkowski S, von Hoff K, Emser A, et al. (November 2010). "Survival and Prognostic Factors of Early Childhood Medulloblastoma: An International Meta-Analysis". J Clin Oncol 28 (33): 4961–4968. doi:10.1200/JCO.2010.30.2299. PMID 20940197.

[8] Rutkowski, S.; Bode, U.; Deinlein, F.; Ottensmeier, H.; Warmuth-Metz, M.; Soerensen, N.; Graf, N.; Emser, A. et al. (Mar 2005). "Treatment of early childhood medulloblastoma by postoperative chemotherapy alone.". N Engl J Med 352 (10): 978-86. doi:10.1056/NEJMoa042176. PMID 15758008.

[9] Ramaswamy, V.; Remke, M.; Bouffet, E.; Bailey, S.; Clifford, SC.; Doz, F.; Kool, M.; Dufour, C. et al. (Jun 2016). "Risk stratification of childhood medulloblastoma in the molecular era: the current consensus.". Acta Neuropathol 131 (6): 821-31. doi:10.1007/s00401-016-1569-6. PMID 27040285.

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