CNS Tumors: Embryonal

Treatment Summary

  • Consists of surgery, post-operative RT, and chemotherapy.
  • Requirement of craniospinal irradiation, regardless of extent of disease, is the element that distinguishes the treatment of these tumors.

Atypical teratoid/ rhabdoid tumor (ATRT)


  • Monosomy 22, deletion of 22q11 and alteration in the 1NI1 gene are characteristic of ATRT
  • NF2-22q11 (Characteristic gene mutations)
  • Imi1-22q11.2 (Characteristic gene mutations)

Prognosis of Atypical teratoid/ rhabdoid tumor (ATRT)

  • Carries worse prognosis compared to PNET, survival beyond 1 to 2 years is anecdotal.

Supratentorial PNET (S-PNET)

  • < 5% of all CNS tumor
  • Median age 3 years
  • Worse prognosis than medulloblastoma: OS-5 of 20%-35%. (medulloblastoma OS-5 of 80%)
  • Standard therapy for patients with sPNET includes :
  • craniospinal irradiation to 36 Gy
  • boost of 54 Gy to the initial tumor.
  • adjuvant chemotherapy (8 in 1 or CCNU, prednisone, and vincristine)
  • four-institution trial
  • aggressive surgery
  • craniospinal irradiation to 23.4 for M0 disease
  • dose-intensive chemotherapy for 4 cylcles (Ref. Strother D)
  • In the CCG 921 study in which neoadjuvant and adjuvant 8-in-1 chemotherapy was compared to adjuvant CCNU, prednisone, and vincristine, each given with radiation therapy, 3-year PFS and survival were 45% and 57%, respectively, for all patients with sPNET and did not differ significantly between the two study arms. (Ref. Cohen BH)



  • Pineoblastoma is most often confused with medulloblastoma histologically and by contiguous anatomic location.


  • Primitive polar spongioblastoma is a rare cerebral tumor thought to be derived rom migrating glial precursor cells.
  • Ependymoblastoma is a pooly differentiated embryonal tumor including ependymal differentiation signified by multilayered rosettes.
  • Cerebral neuroblastoma ranges hitologically from an undifferentiated tumor similar to the extra-CNS childhood neuroblastoma often including unilayered Homer Wright rosettes, to lesions demonstrating considerable ganglionic differentiation.
  • Medulloepithelioma is the most primitive embryonal tumor, histologically showing features of primitive medullary epithelium and primitive tubular structures.
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