Gliosarcoma arising from oligodendroglioma, IDH mutant and 1p/19q codeleted.

Herein, we present a rare case of gliosarcoma arising from oligodendroglioma, isocitrate dehydrogenase (IDH) mutant and 1p/19q codeleted. A 36-year-old man presented with a non-enhanced calcified abnormal lesion on the right frontal lobe. The patient underwent subtotal surgical resection, PAV chemotherapy (procarbazine, nimustine (ACNU) and vincristine), and fractionated radiotherapy with 50 Gy. The pathological diagnosis was oligodendroglioma, IDH mutant and 1p/19q codeleted, World Health Organization 2016 grade II. Six years later, a new enhanced lesion appeared, and the recurrent tumor was surgically removed. Although the histopathological findings indicated gliosarcoma, the recurrent tumor still demonstrated the IDH mutation and 1p/19q codeleted. Thus, the recurrent tumor was considered to originate from oligodendroglioma, rather than being newly generated after chemoradiotherapy. Interestingly, the second recurrent tumor responded well to temozolomide chemotherapy. Based on the findings of this case, oligodendrogliomas have the potential for mesenchymal transformation on progression, while keeping their genotype.

Yasuda T ，Nitta M ，Komori T ，Kobayashi T ，Masui K ，Maruyama T ，Sawada T ，Muragaki Y ，Kawamata T ... -  《-》

Gliosarcoma arising from oligodendroglioma (Oligosarcoma): A case report with genetic analyses.

Gliosarcomas are a type of bimorphic tumor composed of glial and sarcomatous elements, and are considered to be a variant of glioblastoma, WHO grade IV. To date, only rare cases of gliosarcoma with oligodendroglial components (oligosarcoma) have been reported. We report a case of oligosarcoma consisting of gliosarcoma arising from recurrent oligodendroglioma. A 53-year-old man, who had undergone a gross total resection of oligodendroglioma (WHO grade II) 11 years earlier, presented with a local tumor recurrence. The patient underwent a second gross total resection, whereupon a histopathological examination further revealed residual features of classical oligodendroglioma, and newly-developed sarcomatous characteristics. Both the primary and recurrent tumors showed 1p/19q co-deletion and mutation of the isocitrate dehydrogenase 1 (IDH1) gene, consistent with being oligodendroglial in nature. Loss of heterozygosity (LOH) of chromosome 1p/19q and IDH1 mutation have seldom been analyzed in previous reports of oligosarcomas. We report a rare case study supported by the results of genetic analyses. Our analyses have revealed that the sarcomatous component represents a metaplastic change occurring in the oligodendroglial element.

Tanaka S ，Hitotsumatsu T ，Sugita Y ，Ishido K ，Ito O ，Hatae R ，Akagi Y ，Yoshimoto K ，Iihara K ... -  《-》

Loss of H3K27 trimethylation is frequent in IDH1-R132H but not in non-canonical IDH1/2 mutated and 1p/19q codeleted oligodendroglioma: a Japanese cohort study.

Habiba U ，Sugino H ，Yordanova R ，Ise K ，Tanei ZI ，Ishida Y ，Tanikawa S ，Terasaka S ，Sato KI ，Kamoshima Y ，Katoh M ，Nagane M ，Shibahara J ，Tsuda M ，Tanaka S ... -  《Acta Neuropathologica Communications》

Sarcomatous evolution of oligodendroglioma ("oligosarcoma"): confirmatory report of an uncommon pattern of malignant progression in oligodendroglial tumors.

By analogy to gliosarcoma, the neologism "oligosarcoma" is to describe an uncommon form of biphasic central nervous system tumor composed of contiguous neuroepithelial and mesenchymal elements, each of which individually meet the criteria of oligodendroglioma and sarcoma, respectively. By virtue of its distinctive genotype (codeletion 1p/19q), oligodendroglioma is a particularly inviting paradigm to test the assumption that such mixed tumors are clonally derived from a glial primary. We observed this constellation in a 41-year-old male who underwent two resection procedures for a recurring right frontal tumor at five years' interval. On imaging, both lesions were contrast-enhancing, and measured 7 cm × 7 cm × 6.8 cm and 7 cm × 6.5 cm × 4cm, respectively. Following the first operation, temozolomide monotherapy was administered. Whereas initial histology showed conventional anaplastic oligodendroglioma, the recurrence consisted mostly of a fibrosarcoma-like, fascicular neoplasm that was immunoreactive for vimentin, smooth muscle actin, S100 protein, and focally epithelial membrane antigen. In between, a subset of otherwise indistinguishable spindle cells expressed GFAP, and focally merged with residues of oligodendroglioma. Molecular testing for loss of heterozygosity confirmed codeletion of 1p/19q in both the primary tumor and the sarcomatous recurrence. Similarly, generalized immunoreactivity for the mutant R132H form of isocitrate dehydrogenase in both lesions indicated an identical mutation of the IDH1 gene. By the above standards, biologically consistent "oligosarcomas" are felt to be exceedingly rare, and possibly participate of a nosologically heterogeneous group of combined glial/mesenchymal lesions that may also include iatrogenically induced second malignancies as well as true collision tumors.

Vajtai I ，Vassella E ，Hewer E ，Kappeler A ，Reinert MM ... -  《-》

Contrast enhancement in 1p/19q-codeleted anaplastic oligodendrogliomas is associated with 9p loss, genomic instability, and angiogenic gene expression.

Reyes-Botero G ，Dehais C ，Idbaih A ，Martin-Duverneuil N ，Lahutte M ，Carpentier C ，Letouzé E ，Chinot O ，Loiseau H ，Honnorat J ，Ramirez C ，Moyal E ，Figarella-Branger D ，Ducray F ，POLA Network ... -  《-》