Abstract
Purpose
Epithelioid glioblastoma (eGBM) is rare and a newly recognized subtype of GBM. Given the short of studies focusing on radiological characteristics of these tumors, we aimed to report the radiological features of eGBM deriving from six patients.
Methods
Six patients with pathologically diagnosed as eGBM were enrolled in this retrospective study. CT and pre-operative MR examinations with conventional and advanced sequences, such as diffusion weighted imaging and so on were analyzed. Immunohistological staining and mutation analysis of BRAF V600E was also explored.
Results
Only case 6 showed a co-locating tumor which was verified to be a diffuse astrocytoma (WHO II), other cases demonstrated single intracerebral tumor. Majority of the tumors originated in cerebral cortex, two cases involved corpus callosum. Tumors demonstrated iso-, hypo- or mixed intensity on T1WI, hyper- or mixed intensity on T2WI and FLAIR, heterogeneous enhancement on post-contrasted imaging. Involvement of leptomeninge, which appeared as leptomenigeal thickening and abnormal enhancing was discovered in 4 cases. Peritumoral edema (4/6) and hemorrhage (3/6) was common, calcium was only seen in case 5. Notable restrictive diffusion and consequently decreased rADC was found in solid component in 5 cases. Most cases demonstrated increased Cho and Lac/Lip value on 1H-MRS, and promoted rCBV value on PWI. The cases with CT examination showed an ill-defined mass with mixed density.
Conclusions
Although there are some overlaps between typical GBM and eGBM, some radiological characteristics, such as location (often in cerebral cortex), involvement of leptomeninge and intratumoral calcium, may support the diagnosis of eGBM.