Abstract：
\"Oligoastrocytoma\" disappeared as of the revised fourth edition of the World Health Organization Classification of Tumours of the Central Nervous System, except where appended with \"not otherwise specified (NOS)\". However, histopathological and genetic backgrounds of cases with dual features of astrocytoma/oligodendroglioma have been sparsely reported. We encountered a 54-year-old man with right frontal glioma comprising two distinct parts on imaging and histopathological examination: grade 4 astrocytoma with IDH1-R132H, ATRX loss, p53-positivity and intact 1p/19q; and oligodendroglioma with IDH1-R132H, intact ATRX, p53-negativity and partially deleted 1p/19q. At recurrence, histopathology showed low-grade mixed astrocytic and oligodendroglial features: the former with IDH1-R132H, ATRX loss, p53-positivity and intact 1p/19q and the latter showing IDH1-R132H, intact ATRX, p53-negativity and 1p/19q codeletion. At second recurrence, histopathology was astrocytoma grade 4 with IDH1-R132H, ATRX loss, p53-positivity and intact 1p/19q. Notably, 1p/19q codeletion was acquired at recurrence and CDKN2A was deleted at second recurrence. These findings suggest insights into tumorigenesis: (1) gliomas with two distinct lineages might mix to produce \"oligoastrocytoma\"; and (2) 1p/19q codeletion and CDKN2A deletion might be acquired during chemo-radiotherapy. Ultimately, astrocytic and oligodendroglial clones might co-exist developmentally or these two lineages might share a common cell-of-origin, with IDH1-R132H as the shared molecular feature.
摘要：
“寡星形细胞瘤”在世界卫生组织中枢神经系统肿瘤分类第四版修订版中消失，除非附加了“未指定(NOS)”。然而,具有星形细胞瘤/少突胶质细胞瘤双重特征的病例的组织病理学和遗传背景的报道很少。我们遇到了一名54岁的右额叶神经胶质瘤，在影像学和组织病理学检查中包括两个不同的部分：4级星形细胞瘤，IDH1-R132H，ATRX损耗,p53阳性和完整的1p/19q;和具有IDH1-R132H的少突胶质细胞瘤，完整的ATRX,p53阴性和部分缺失1p/19q。在复发时，组织病理学显示低度混合星形胶质细胞和少突胶质细胞特征：前者具有IDH1-R132H，ATRX损耗,p53阳性和完整的1p/19q，后者显示IDH1-R132H，完整的ATRX,p53阴性和1p/19q共缺失。在第二次复发时，组织病理学为星形细胞瘤4级，IDH1-R132H，ATRX损耗,p53阳性和完整的1p/19q。值得注意的是,复发时获得1p/19q共缺失，第二次复发时删除CDKN2A。这些发现表明了对肿瘤发生的见解：（1）具有两个不同谱系的神经胶质瘤可能混合产生“寡星形细胞瘤”；（2）在化疗期间可能会获得1p/19q共缺失和CDKN2A缺失。最终,星形胶质细胞和少突胶质细胞克隆可能在发育中共存，或者这两个谱系可能共享一个共同的起源细胞，以IDH1-R132H为共有分子特征。
