CNS tumor
Embryonal tumors
Other embryonal tumors
Atypical teratoid / rhabdoid tumor
Deputy Editor-in-Chief: Debra Zynger, M.D.
Topic Completed: 30 September 2019
Minor changes: 23 July 2020
Copyright: 2002-2020, PathologyOutlines.com, Inc.
PubMed Search: Atypical teratoid/rhabdoid tumor (ATRT)
Table of Contents
Definition / general | Essential features | ICD coding | Epidemiology | Sites | Clinical features | Grading | Radiology description | Radiology images | Prognostic factors | Case reports | Treatment | Microscopic (histologic) description | Microscopic (histologic) images | Cytology images | Positive stains | Negative stains | Molecular / cytogenetics description | Board review style question #1 | Board review answer #1Cite this page: Singh N, Biggs PJ. Atypical teratoid / rhabdoid tumor. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cnstumoratypicalteratoidrhabdoid.html. Accessed August 14th, 2020.
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
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
- 10 month old girl with rapidly progressive paraplegia (Clin Neuropathol 2006;25:81)
- 16 month old boy with progressive urinary retention (Spinal Cord Ser Cases 2017;3:16026)
- 7 year old boy with spinal atypical teratoid / rhabdoid tumor (Neuropathology 2007;27:139)
- Adolescent with an ATRT and simultaneous low grade glioneuronal tumor (J Pediatr Hematol Oncol 2017;39:e456)
- Adolescent with atypical teratoid rhabdoid tumor involving the nasal cavities and anterior skull base (Neuropathology 2016;36:283)
- 19 year old man with atypical teratoid / rhabdoid tumor of the pineal region (J Neurol Surg A Cent Eur Neurosurg 2017;78:92)
Treatment
- Surgery, high dose chemotherapy with radiation (Pediatr Blood Cancer 2017 Dec;64(12))
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
Cytology images
Images hosted on other servers:
Typical cytology
Positive stains
- Rhabdoid cells are positive for EMA, SMA and vimentin
- Cytokeratins, GFAP, NFP and synaptophysin staining are also observed
Molecular / cytogenetics description
- Loss of SMARCB1 expression at the protein level is seen in most ATRT tumors (Cancer Biol Ther 2009;8:412, Pediatr Dev Pathol 2018;21:6, Neuropathology 2018;38:305)
Board review style question #1
Atypical rhabdoid / teratoid tumor is diagnosed by:
- NMYC amplication
- SMARCB1 and SMARCA4 genes
- TP53 mutation
- Tumor cells with high N/C ratios and frequent smudge artifacts on smears
Board review answer #1
B. SMARCB1 is the most common and SMARCA4 is more rare
