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Background: Bevacizumab (BEV), a humanized monoclonal antibody, become a currently important chemotherapeutic option for the patients with recurrent glioma. The aim of this retrospective study is to investigate whether 18F-Fluoromisonidazole (FMISO) PET have the potential to detect BEV-resistant gliomas in the early-stage. Methods: We reviewed the FMISO PET and MRI appearances before and 3 to 4 courses after BEV treatment on 18 recurrent glioma patients. FMISO accumulation was assessed by visual inspection and semi-quantitative values which were tumor-to-normal (T/N) ratio and hypoxic volume. MRI responses were evaluated based on RANO (Response Assessment in Neuro-Oncology) criteria. The prognostic analysis was performed in relation to the response assessment by FMISO PET and MRI using overall survival (OS) after BEV application. Results: After BEV application, MRI revealed partial response in 14 of 18 patients (78%), of which 9 patients also demonstrated decreased FMISO accumulation. These 9 patients (50%) were classified as “MRI-FMISO double responder”. As for the other 5 patients (28%), FMISO accumulation volumes increased or remained stable after BEV treatment although partial responses were achieved on MRI. Therefore, these cases were classified as “MRI-only responder”. The remaining 4 patients (22%) did not show treatment response on FMISO PET or MRI (“non-responder”). MRI-FMISO double responders showed significantly longer OS than that in other groups (median 12.4 vs 5.7 months; P < 0.001), whereas there were no overall survival difference between MRI-only responders and non-responders (median OS, 5.7 and 4.8 months; P = 0.58). Among the pre-treatment clinical factors, high FMISO T/N ratio was a significant prognostic factor of overall survival in these patients under the assessment of Cox proportional hazard model. Conclusions: Recurrent gliomas with decreasing FMISO accumulation after short-term BEV application could derive a survival benefit from BEV treatment. Change in FMISO PET appearance can identify BEV-resistant gliomas in early-stage regardless of MRI findings in a comprehensible way. [ABSTRACT FROM AUTHOR]

In the CNS, primary tumors with rhabdoid components are classified as atypical teratoid/rhabdoid tumor, rhabdoid meningioma or rhabdoid glioblastoma. The authors present a young adult patient with supratentorial rhabdoid tumor incidentally found after head trauma as a small pre-existing lesion in the parahippocampal gyrus. MRI demonstrated an area of hypointensity on T1-weighted images and hyperintensity on T2-weighted and fluid attenuated inversion recovery images. A serial MR scan revealed no change 3 months after the initial examination but drastic changes at 6 months. As the tumor and accompanying intratumoral hemorrhage enlarged rapidly, resection of the tumor was performed. Histopathology revealed that the main component of the tumor was typical rhabdoid cells with some necrotic areas. There were also pathological features consistent with oligoastrocytoma. The specimen had neither vascular proliferation usually seen in high-grade glioma nor the meningothelial pattern that suggests meningioma. Immunohistochemical findings revealed that cells were strongly positive for vimentin, epithelial membrane antigen and INI-1 antibody throughout the specimen. Further, monosomy 22 was detected by fluorescence in situ hybridization. The tumor was finally thought to be an unclassifiable primitive rhabdoid tumor with oligoastrocytoma that arose in the CNS. The patient died within 5 months of detection of the tumor, regardless of surgical resection, radiotherapy and chemotherapy. [ABSTRACT FROM AUTHOR]