MRI features of pediatric atypical teratoid rhabdoid tumors and medulloblastomas of the posterior fossa

Background: Atypical teratoid rhabdoid tumor (AT/RT) occurs at a younger age and is associated with a worse prognosis than medulloblastoma; however, these two tumor entities are mostly indistinguishable on neuroimaging. The aim of our study was to differentiate AT/RT and medulloblastoma based on their clinical and MRI features to enhance treatment planning and outcome prediction.Methods: From 2005-2021, we retrospectively enrolled 16 patients with histopathologically diagnosed AT/RT and 57 patients with medulloblastoma at our institute. We evaluated their clinical data and MRI findings, including lesion signals, intratumoral morphologies, and peritumoral/distal involvement.Results: The age of children with AT/RT was younger than that of children with medulloblastoma (2.8 +/- 4.9 [0-17] vs. 6.5 +/- 4.0 [0-18], p < 0.001), and the overall survival rate was lower (21.4% vs. 66.0%, p = 0.005). Regarding lesion signals on MRI, AT/RT had a lower ADC(min) (cutoff value & LE;544.7 x 10(-6) mm(2)/s, p < 0.001), a lower ADC ratio (cutoff value <= 0.705, p < 0.001), and a higher DWI ratio (cutoff value >=;1.595, p < 0.001) than medulloblastoma. Regarding intratumoral morphology, the tumor central vein sign was mostly exclusive to medulloblastoma (24/57, 42.1%; AT/RT 1/16, 6.3%; p = 0.007). Regarding peritumoral invasion on T2WI, AT/RT was more prone to invasion of the brainstem (p < 0.001) and middle cerebellar peduncle (p < 0.001) than medulloblastoma.Conclusions: MRI findings of a lower ADC value, more peritumoral invasion, and absence of the tumor central vein sign may be helpful to differentiate AT/RT from medulloblastoma. These distinct MRI findings together with the younger age of AT/RT patients may explain the worse outcomes in AT/RT patients.

Automated summary

This study aimed to differentiate atypical teratoid rhabdoid tumor (AT/RT) from medulloblastoma based on clinical and MRI features. MRI findings, including lower ADC value, more peritumoral invasion, and absence of the tumor central vein sign, may be helpful in distinguishing AT/RT from medulloblastoma.