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Updated: Feb 10, 2026
Primary Orthotopic Glioma Xenografts Recapitulate Infiltrative Growth and Isocitrate Dehydrogenase I Mutation
Published on: January 14, 2014
Recurrent pseudoprogression in isocitrate dehydrogenase 1 mutant glioblastoma
Sied Kebir1, Laurèl Rauschenbach2, Gerrit H Gielen3
1Division of Clinical Neurooncology, Department of Neurology, University Hospital Essen, University Duisburg-Essen, Essen, Germany; Division of Clinical Neurooncology, Department of Neurology, University Hospital Bonn, University of Bonn, Bonn, Germany; West German Cancer Center (WTZ) & German Cancer Consortium (DKTK) Partner Site, University Hospital Essen, University Duisburg-Essen, Essen, Germany; Division of Translational Oncology/Neurooncology, German Cancer Consortium (DKTK) Partner Site, University Hospital Essen, Essen, Germany.
Abstract:
In a subset of glioblastoma (GBM) patients, the differentiation between tumor progression and tumor pseudoprogression (PsP) is challenging. This case describes a male patient suffering from isocitrate dehydrogenase 1 (IDH1) mutant GBM who demonstrated an increasing contrast-enhancing (CE) lesion on a cranial magnetic resonance imaging (cMRI) scan 8 months after radiochemotherapy. In accordance with the response assessment in neuro-oncology (RANO) criteria, the cMRI lesion was classified as recurrent tumor, although 18F-fluoroethyl-L-tyrosine positron emission tomography (18F-FET-PET) did not indicate vital tumor tissue. The patient underwent re-surgery but histopathology only revealed reactive and necrotic tissue, consistent with PsP. Nine weeks after complete resection of the CE lesion, a new lesion emerged that later regressed in the follow-up cMRI scans, thereby retrospectively establishing the diagnosis of recurrent PsP.
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