Atypical Teratoid/Rhabdoid Tumour (ATRT)

Epidemiology and Etiology:

· Childhood

· Has been misclassified as PNET or medulloblastoma

· Unknown cell type

· polyphenotypic

Common sites:

· brain

· liver

· soft tissues

Gross features:

·

Histologic features:

·

Immunophenotype:

Marker:	Sensitivity:	Specificity:
INI1 / hSNF5 / SMARCB1 (negative for protein product)
Neural markers
Epithelial markers
Mesenchymal markers

Molecular features:

· 22q deletion (most frequent alteration)

· INI1 / hSNF5 / SMARCB1

· Mutation of INI1 / hSNF5 / SMARCB1

· Sporadic mutation in addition to 22q deletion often

· Germline mutation may be present in up to 1/3 of patients

Other features:

· Highly aggressive

· Often metastatic at the time of diagnosis

· Respond poorly to therapy

·

References:

· Heim S, Mitelman F. Cancer Cytogenetics. 3rd ed. Wiley-Blackwell; 2009.