Paediatric CNS atypical teratoid/rhabdoid tumour, AT/RT

AT/RT is a highly malignant embryonal CNS tumour.

Histopathology

Rhabdoid cells are present. In addition, there may be primitive neuroectodermal, mesenchymal or epithelial cells.

Immunohistochemistry

The co-expression of epithelial and mesenchymal antigens is characteristic but not specific.

Cytogenetics and molecular genetics

A hSNF/INI1 mutation is found in 75% of rhabdoid tumours. Loss of INI1 expression is associated with a deletion at 22q11.21.

Differential diagnosis

• Supratentorial PNET

• Medulloblastoma

• Anaplastic ependymoma

• Choroid plexus carcinoma: an overlap with AT/RT has been suggested

• Glioblastoma

• Malignant teratoma

Management

Although unresponsive to conventional adjuvant therapy, there appears to be better survival with recent aggressive therapies.

References

1 Haberler C, Laggner U, Slavc I, et al. Immunohistochemical analysis of INI1 protein in malignant pediatric CNS tumors: Lack of INI1 in atypical teratoid/rhabdoid tumors and in a fraction of primitive neuroectodermal tumors without rhabdoid phenotype. Am J Surg Pathol 2006; 30:1462-8

This page last revised 1.1.2007.

©SMUHT/PW Bishop