CNS tumor
Embryonal tumors
Other embryonal tumors
Atypical teratoid / rhabdoid tumor

Deputy Editor-in-Chief: Debra L. Zynger, M.D.
Nirupama Singh, M.D., Ph.D.
Paul J. Biggs, M.D.

Topic Completed: 30 September 2019

Minor changes: 20 April 2021

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PubMed Search: Atypical teratoid/rhabdoid tumor (ATRT)

Nirupama Singh, M.D., Ph.D.
Paul J. Biggs, M.D.
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Cite this page: Singh N, Biggs PJ. Atypical teratoid / rhabdoid tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cnstumoratypicalteratoidrhabdoid.html. Accessed July 27th, 2021.
Definition / general
  • Malignant CNS embryonal tumor composed of poorly differentiated cells including rhabdoid cells
  • Occurs in young children; diagnosis is based on demonstrating loss of INI1
  • Tumors with similar morphology but lacking characteristic molecular findings are classified as CNS embryonal tumors with rhabdoid features
Essential features
  • Loss of SMARCB1 or SMARCA4 genes is required for the diagnosis of atypical teratoid / rhabdoid tumor (ATRT)
  • Tumors with similar morphology but lacking this mutation are classified as CNS embryonal tumor with rhabdoid features
ICD coding
  • C71: malignant neoplasm of brain
Epidemiology
  • Accounts for 1 - 2% of all pediatric brain tumors and is very rare in adults
  • Age typically < 3 years; rare in children aged > 6 years
  • Can occur in cerebral hemispheres, cerebellum or rarely in the spinal cord
Sites
  • Cerebral hemispheres, cerebellar hemispheres, cerebellopontine angle, brain stem
  • In adults, the most common site is cerebral hemispheres
Clinical features
  • Depends on age and location
  • In infants, lethargy, vomiting and failure to thrive are common symptoms
  • If > 3 years, headache and hemiplegia are reported
  • Cranial nerve palsy (mostly 6 and 7 nerve paresis) may also be present
Grading
  • WHO grade IV
Radiology description
  • Isodense to hyperintense on FLAIR images with restricted diffusion
Radiology images
Contributed by Dr. Chunyu "Hunter" Cai (Case #502)

MRI T1 post saggittal



Images hosted on other servers:

ATRT in a 9 month old

Prognostic factors
  • Poor; 5 year progression free and overall survival rate is only 60% even for the favorable group
Case reports
Treatment
Microscopic (histologic) description
  • Diagnostic feature on histology is the presence of cells with rhabdoid features, which include:
    • Well defined cell borders
    • Abundant cytoplasm with eosinophilic inclusions
    • Eccentrically located nuclei containing vesicular chromatin
    • Prominent eosinophilic nucleoli
  • Cytoplasm is granular
  • Primitive neuroectodermal component is most common
  • Mesenchymal and epithelial features are less common
Microscopic (histologic) images

Contributed by Nirupama Singh, M.D., Ph.D.

Tumor cells with nucleus showing vesicular chromatin and prominent nucleoli

Eosinophilic globs

Mitotic figures



Contributed by Dr. Chunyu "Hunter" Cai (Case #502)
H&E myxoid area

H&E myxoid area

H&E chondroid

H&E chondroid

H&E geographic necrosis

H&E geographic necrosis

H&E gland

H&E gland


H&E large pale cell

H&E large pale cell

H&E rhabdoid cell

H&E rhabdoid cell

H&E small blue cell

H&E small blue cell

INI1

INI1

Cytology images

Images hosted on other servers:

Typical cytology

Positive stains
Negative stains
  • Germ cell markers and skeletal muscle differentiation markers (MyoD1, myogenin)
Molecular / cytogenetics description
Board review style question #1
Atypical rhabdoid / teratoid tumor is diagnosed by:

  1. NMYC amplication
  2. SMARCB1 and SMARCA4 genes
  3. TP53 mutation
  4. Tumor cells with high N/C ratios and frequent smudge artifacts on smears
Board review style answer #1
B. SMARCB1 is the most common and SMARCA4 is more rare

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Reference: Atypical teratoid / rhabdoid tumor
Board review style question #2
Which of the following is the most common age range when AT/RT presents?

  1. 0 - 3 years
  2. 3 - 20 years
  3. 20 - 50 years
  4. 50 - 80 years
Board review style answer #2
A. 0 - 3 years. More than 80% of AT/RTs are diagnosed before age 3.

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Reference: Atypical teratoid / rhabdoid tumor
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