RSNA Case Collection
Primary Glioblastoma :
Imaging findings, as well as the pathology report, confirmed the suspicion for primary glioblastoma. Imaging demonstrates a mass within the left parietotemporal region with the typical findings of primary glioblastoma including large size, hemorrhage, necrosis, mass effect, neovascularity, and surrounding edema/infiltrative tumor spread. The pathology report specifically revealed Glioblastoma, WHO grade IV, IDH wild type, and ATRX (ATP-dependent helicase) expression retained.
Differential diagnoses:Intracranial abscess :
Intracranial abscess characteristically demonstrates peripheral ring enhancing wall on post contrast imaging with central light bulb bright diffusion signal and low ADC value.
Metastasis are more frequently multiple and tend to occur at the grey-white matter junction. Metastasis usually show a higher degree of surrounding vasogenic edema.Tumefactive demyelinating lesion (TDL) :
Tumefactive demyelinating lesions demonstrate a variable post contrast enhancement pattern, but a pattern of an open ring/horseshoe is characteristic. These lesions tend to be larger with relatively little surrounding vasogenic edema or mass effect.
Primary CNS Lymphoma :
Lymphoma would exhibit solid homogeneous enhancement on post-contrast imaging in immunocompetent patients; atypical lymphomas or lymphomas in immunocompromised patients can exhibit necrotic areas and may mimic GBM.
Carrillo M, Waldrop M, Malay N. Primary glioblastoma. RSNA Case Collection 2021 May 21; doi: 10.1148/cases.20224085.