BACKGROUND AND PURPOSE Gliosarcoma (GSC) is an intra‐axial lesion which often abuts a dural margin and is composed of glial and mesenchymal elements. This lesion is considered a variant of isocitrate dehydrogenase (IDH)‐wild type glioblastoma (GBM). The purpose of this study is to evaluate the imaging and molecular features of GSC in a large patient cohort. METHODS Pathology‐proved GSC cases were collected from our quaternary care center spanning the last 16 years and IDH status was documented. Older GSC cases without prior immunohistochemical testing underwent tissue block staining to obtain IDH status. When available, p53, phosphate and tensin (PTEN), MIB‐1, EGFR amplification, and MGMT methylation were recorded and imaging findings tabulated. Logistic regression analyses were performed to determine correlation of molecular markers and imaging characteristics. RESULTS A total of 25 cases were identified (21 de novo, 4 post‐treatment). All lesions contacted a dural, pial, or ependymal surface and were negative for an IDH R132H mutation, including postradiation GSC. In total, 16 of 16 cases showed nonamplification of EGFR/CEP7, 2 of 16 demonstrated MGMT methylation, and multiple lesions demonstrated p53 and PTEN mutations. Imaging features included areas of nodular thickening in necrotic lesions which appeared to abut the site of dural contact. There was no significant correlation of molecular markers with imaging characteristics. CONCLUSION GSC was IDH(–) in all cases, supporting the current understanding of this lesion being a wild‐type GBM variant. Additional molecular markers demonstrated no significant correlation with imaging findings in this cohort.

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We present 5 cases of demyelination in patients diagnosed with multiple sclerosis that are closely associated with a developmental venous anomaly. Although the presence of a central vein is a known phenomenon with multiple sclerosis plaques, demyelination occurring around developmental venous anomalies is an underreported phenomenon. Tumefactive demyelination can cause a diagnostic dilemma because of its overlapping imaging findings with central nervous system neoplasm. The relationship of a tumefactive plaque with a central vein can be diagnostically useful, and we suggest that if such a lesion is closely associated with a developmental venous anomaly, an inflammatory or demyelinating etiology should be a leading consideration.

The exiting L5 nerve can allow accurate localization of the corresponding vertebrae, which is essential for preprocedure planning in cases where full spine imaging is not available. This neuroanatomic method displays higher agreement with the reference standard compared with previously described methods, with strong inter- and intrarater reliability.