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Atypical Teratoid-Rhabdoid Tumor (AT/RT)

Last Updated: March 27, 2020

Open Table of Contents: Atypical Teratoid-Rhabdoid Tumor (AT/RT)

Figure 1: Axial NECT (top row left) demonstrates a heterogeneous, mildly hyperdense ATRT in the posteromedial left cerebellum. There is associated mass effect on the cerebellum and 4th ventricle. Axial T2WI (top row right) shows cystic change within this tumor. Abnormality in the medulla represents leptomeningeal metastasis of tumor with associated invasion. ADC (bottom row left) shows dark restricted diffusion of hypercellularity within the tumor. Axial T1WI post contrast (bottom row right) shows the avid enhancement and cystic changes of this high grade tumor.

Figure 2: This ATRT demonstrates stereotypical high complexity, with solid and cystic/necrotic components, surrounding hyperintense vasogenic edema (top row left – T2, top row right – FLAIR), restricted diffusion indicating hypercellularity (second row left – DWI, second row right – ADC) and heterogeneous contrast enhancement (third row right, bottom row left, bottom row right) when compared to the pre-contrast T1 (third row left). This ATRT is atypical in its supratentorial location, these tumors usually being infratentorial. ATRTs are also often indistinguishable by imaging alone from other highly complex pediatric brain tumors such as PNET and medulloblastoma.

Basic Description

  • Aggressive, infiltrative pediatric rhabdoid tumor with highly variable appearance and histology

Pathology

  • WHO grade IV
  • Involves mesenchymal, neuronal, glial, and epithelial cell lines (“teratoid”)
    • ± Rhabdoid cells, primitive neuroectodermal cells
  • Mutations of SMARCB1/hSNF5 and loss of INI1 protein is diagnostic of AT/RT
  • Familial mutations in rhabdoid tumor predisposition syndrome (RTPS)

Clinical Features

  • Most commonly afflicts children <3 years and usually in the posterior fossa; tumors in adults are often in atypical locations
  • No gender predilection
  • Common presenting signs/symptoms related to increased intracranial pressure/hydrocephalus
    • Vomiting, altered mental status, macrocephaly
  • Treatment: surgical resection ± adjuvant chemoradiation

    • Often unresectable
  • Prognosis: overall 5-year survival less than 30%

    • Survival with leptomeningeal spread: 16 months
    • Survival without leptomeningeal spread: 149 months

Imaging Features

  • General
    • Highly variable, nonspecific morphology and imaging characteristics
    • Supra- or infratentorial
      • More than half arise within the posterior fossa
    • Variable size; often large at time of diagnosis
    • Mixed solid-cystic mass
    • ± Calcification, hemorrhage, and necrosis
    • ± Obstructive hydrocephalus
    • Leptomeningeal/CSF dissemination common (>30%)
  • CT

    • Hyperdense mass
    • Hyperdense calcification and hemorrhage or hypodense cysts may be seen
    • Avid, heterogeneous enhancement on contrast-enhanced CT
  • MRI

    • T1WI: heterogeneous signal due to cystic or hemorrhagic components
    • T2WI: heterogeneous signal due to cystic or hemorrhagic components
    • FLAIR: heterogeneous, hyperintense periventricular signal due to hydrocephalus/interstitial edema, little peritumoral edema
    • T2*GRE: hypointense signal due to calcification and hemorrhage
    • T1WI+C: majority show heterogeneous enhancement, may see enhancing CSF dissemination along the brain, cranial nerves, spinal nerves, or spinal cord
    • DWI: demonstrates diffusion restriction in hypercellular regions of tumor
    • MR spectroscopy: elevated Cho, decreased NAA, ± lactate/lipid peaks

Imaging Recommendations

  • MRI without and with IV contrast including both brain and spine due to risk of CSF dissemination

For more information, please see the corresponding chapter in Radiopaedia.

Contributor: Rachel Seltman, MD

DOI: https://doi.org/10.18791/nsatlas.v1.03.01.03

References

Bruggers CS, Moore K. Magnetic resonance imaging spectroscopy in pediatric atypical teratoid rhabdoid tumors of the brain. J Pediatr Hematol Oncol. 2014;36:e341-345.

Koral K, et al. Imaging characteristics of atypical teratoid-rhabdoid tumor in children compared with medulloblastoma. AJR Am J Roentgenol. 2008;190:809-814.

Margol AS, et al. Pathology and diagnosis of SMARCB1-deficient tumors. Cancer Genet. 2014;207:358-364.

Meyers SP, et al. Primary intracranial atypical teratoid/rhabdoid tumors of infancy and childhood: MRI features and patient outcomes. AJNR Am J Neuroradiol. 2006;27:962-971.

Osborn AG, Salzman KL, Jhaveri MD. Diagnostic Imaging (3rd ed). Philadelphia, PA: Elsevier, 2016.

Parmar H, et al. Imaging findings in primary intracranial atypical teratoid/rhabdoid tumors. Pediatr Radiol. 2006;36:126-132.

Warmuth-Metz M, et al. CT and MR imaging in atypical teratoid/rhabdoid tumors of the central nervous system. Neuroradiology. 2008;50:447-452.

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