Excerpta Extraordinaire
Excerpta #: EE-20
Imaging findings of Atypical Teratoid /
Rhabdoid tumor in a 11-Year Old Boy
H Nakamura 1 , T Suzuki 1 , M Uchida 2 , M Doi 3 , M Takagi 3 , Y
Tanaka 2 , Y Nakajima 2 ,
St. Marianna University of Medicine, Radiology 1 and
Neurodsurgery 2 and Pahtology 3 Kawasaki Japan .

The authors do not have a financial relationship with a commercial organization that may have a direct or indirect interest in the content.

Atypical teratoid / rhabdoid tumors (AT/RT) are rare aggressive neoplasms occurring in children younger than 2 years of age at the infratentorial.
We demonstrate an atypical case of supratentorial AT/RT in a 11-year-old boy.

. A 11-year-old boy came to our hospital complaining of mild headache and nausea, which had been continued for a month.

CT shows a large heterogeneous mass in the left frontal lobe, which contains two parts of iso density on the ventral side and low density on the dorsal side.
Due to mass effect, ventricle , especially on the left side, is obliterated.
Black arrow indicates small high density suggesting calcification.

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Solid part (yellow arrow) - heterogeneous intensity on
DWI, iso and high heterogeneous intensity on T2 WI and FLAIR , low and iso heterogeneous intensity on
T1 WI and mild to moderate contrast enhancement on contrast images. MRS shows decreased NAA and prominent choline peak, suggesting cell membrane turn over.
Necrotic or cystic part - low intensity on DWI and T1 WI, high signal on T2 WI, and no contrast enhancement
Calcification and hemorrhage ( white arrow on T2*)

Large mass with solid and cystic component.
Calcification and hemorrhage
High choline peak.

Pilocytic astrocytoma
Pleomorphic xanthoastrocytoma
AT/RT
Primitive Neuroectodermal Tumor (PNET)
Glioma (glioblastoma, oligodendroglioma)
(anaplastic ) ependymoma
Desmoplastic infantile ganglioglioma/astrocytoma

Tumor shows well-defined margin
Solid and cystic tumor
Success of total removal

H&E stain on high power shows large pleomorphic cells with abundant eosinophilic cell and cells with large eccentrically located nucleus, which are characteristic of rhabdoid cells
.

immunohistochemistry stain for INI-1 on high power shows lack of staining (brown) in tumor cells with retention of staining in non-tumor cells.

Highly malignant embryonal neoplasm
(grade 4 according to the World Health
Organization classification) that typically occurs in children aged <3 years and
6.7% of CNS neoplasm children aged <
3years 1
Most often reported as infratentorial 2, 3

Older than 10years -12% 2 , 9.1% 3
Adult onset almost 30 cases were reported and they favor the supratentorial 4
Some reports show supratentorial is more prevalent or comparative
2, 5

Characteristic “rhabdoid” phenotype ( large immature rhabdoid cells) are helpful for the diagnosis of AT/RT if present, however are not always seen.
Pathologically , AT/RT has considerable overlap with medulloblastoma/PNET
Cytogenetic evaluation of CNS AT/RT and renal AT/RT has revealed deletions and mutations of the INI1 locus in chromosome 22
INI1 thought to represent a tumor suppressor gene
The immunohistochemical reagent for INI1 fails to stain the nuclei of tumor cells with INI1 mutations

Only imaging findings can not distinguish from other high-grade tumors
Thick heterogeneous enhancing wall surrounding a central cyst or cysts is the key feature in differentiation from others 6

The imaging feature is typical findings of
AT/RT
Supratentorial location and the age older
10 years are not typical, but not very rare

When we see the supratentorial solid and cystic tumor even aged
>10 years , differential diagnosis should include AT/RT

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Epidemiology, and End Results analysis. Cancer 2012;118:4212-4219
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3. Warmuth-Metz M, Bison B, Dannemann-Stern E, et al. CT and MR imaging in atypical teratoid/rhabdoid tumors of the central nervous system. Neuroradiology
2008;50:447-452
4. Han L, Qiu Y, Xie C, et al. Atypical teratoid/rhabdoid tumors in adult patients: CT and MR imaging features. AJNR American journal of neuroradiology
2011;32:103-108
5. Jin B, Feng XY. MRI features of atypical teratoid/rhabdoid tumors in children.
Pediatric radiology 2013;43:1001-1008
6. Au Yong KJ, Jaremko JL, Jans L, et al. How specific is the MRI appearance of supratentorial atypical teratoid rhabdoid tumors? Pediatric radiology
2013;43:347-354