MRI features of atypical teratoid/rhabdoid tumors in children

Atypical teratoid/rhabdoid tumors (AT/RTs) are rare, highly malignant tumors of the central nervous system, usually occurring in young children. To investigate the MRI features of AT/RT, with special emphasis on diffusion-weighted imaging (DWI) and MR spectroscopy (MRS). MRI findings of 11 children with AT/RT were reviewed retrospectively, including DWI in 9 AT/RT children and MRS in 6 children. The neoplasms were infratentorial in 4 children and supratentorial in 5 children, both infra- and supratentorial in 1 child and multifocal in 1 child. AT/RT produced heterogeneous signal intensity from peripheral cysts in 7/11 (63%) and hemorrhage in 7/11 (63%). All lesions showed contrast enhancement of varying degrees. Seven (63%) had peritumoral edema. Nine (82%) were hyperintense on DWI with a mean +/- SD ADC of 0.60 +/- 0.13 x 10(-3) mm(2) s(-1). Six lesions (55%) exhibited elevated levels of choline and decreased NAA, and three had lipid peaks. A childhood intracranial tumor with off-midline location, peripheral cystic components, hemorrhage, low ADC, and lipid peaks on MRS suggests AT/RT to be considered a differential diagnosis.