Magnetic Resonance Imaging Features of Rhabdoid Glioblastomas.

Abstract

Rhabdoid glioblastoma (rGB) is a recently described, highly aggressive brain tumor, in which glioblastoma (GB) is associated with a rhabdoid component. So far only 21 cases have been reported and its imaging findings have not been studied in detail. In this paper, we present 11 additional cases and aim to depict detailed magnetic resonance imaging (MRI) features of this tumor in comparison with the previous cases of rGBs and our cohort of typical GBs. Retrospective evaluation of the glass slides of 249 GB patients disclosed 14 cases with rhabdoid morphology. Eleven of these cases with available MRI were included in the study. Immunohistochemistry was also performed. MRI and clinicopathologic findings were compared with those of previous rGBs and typical GBs. (1) rGB is usually a large, well-delineated solid tumor with extensive necrosis, heterogeneous contrast enhancement, occasional hemorrhage, and cysts, (2) rGB may present at an older age than previously reported, but still in younger individuals compared with typical GB patients, (3) tumor dissemination in the form of leptomeningeal seeding and more rarely extracranial metastases is a feature of rGBs, although leptomeningeal seeding may not be as high as previously reported, (4) prognosis is poor in rGBs. rGB is a new entity which has not yet appeared in the WHO classification of central nervous system (CNS) tumors. Understanding its clinical and imaging features may help to distinguish it from other tumors of CNS.