atypical teratoid/rhabdoid tumour
Pronunciation: ay-TIP-ih-kal ter-ah-TOY-d RAB-doyd TOO-mer
A highly malignant embryonal CNS tumour of infancy and early childhood characterised by loss of SMARCB1 (INI1) or, rarely, SMARCA4 protein expression.
Full Definition
Atypical teratoid/rhabdoid tumour (AT/RT) is among the most aggressive paediatric brain tumours, typically occurring in children under three years of age and carrying a median survival of less than two years without intensive therapy. The tumour is defined by biallelic inactivation of SMARCB1 (encoding INI1) or, in a minority of cases, SMARCA4, with loss of nuclear expression confirmed by immunohistochemistry. Three molecular subgroups (AT/RT-TYR, AT/RT-SHH, AT/RT-MYC) have distinct epigenetic profiles and clinical behaviours. Editors should use the solidus (/) rather than a hyphen in 'AT/RT' and should note that the full form uses a forward slash between 'teratoid' and 'rhabdoid', which is non-standard punctuation that must be preserved.
Usage
Usage note: The solidus (/) between 'teratoid' and 'rhabdoid' is part of the official name and must be retained in all editorial contexts.
In Context
- "Loss of INI1 nuclear immunoreactivity confirmed the diagnosis of atypical teratoid/rhabdoid tumour in the nine-month-old infant." — Neuropathology report
- "The solidus in AT/RT is intentional and must not be replaced with a hyphen during copy-editing." — Editorial style note