Magnetic resonance imaging surrogates of molecular subgroups in atypical teratoid / rhabdoid tumor (ATRT)

Abstract

Background

Recently, three molecular subgroups of atypical teratoid/rhabdoid tumor (ATRT) were identified, but little is known on their clinical and magnetic resonance imaging (MRI) characteristics.

Methods

A total of 43 patients with known molecular subgroup status (ATRT-SHH n=17, ATRT-TYR n=16, ATRT-MYC n=10) were retrieved from the EU-RHAB registry and analyzed for clinical and MRI features.

Results

On MRI review, differences in preferential tumor location were confirmed, with ATRT-TYR being predominantly located infratentorially (p<.05). Peritumoral edema was more pronounced in ATRT-MYC, compared to ATRT-SHH (p<.05) and ATRT-TYR (p<.05). Conversely, peripheral tumor cysts were found more frequently in ATRT-SHH (71%) and ATRT-TYR (94%), as compared to ATRT-MYC (40%, p<.05). Contrast enhancement was absent in 29% of ATRT-SHH (0% of ATRT-TYR; 10% of ATRT-MYC; p<.05), and there was a trend towards strong contrast enhancement in ATRT-TYR and ATRT-MYC. We found the characteristic (band-like) enhancement in 28% of ATRT as well as restricted diffusion in the majority of tumors. A midline/off-midline location in the posterior fossa was also not subgroup-specific. Visible meningeal spread (M2) at diagnosis was rare throughout all subgroups.

Conclusions

These exploratory findings suggest that MRI features vary across the three molecular subgroups of ATRT. Within future prospective trials, MRI may aid diagnosis and treatment stratification.