PDF(Pubmed)
Abstract：
Diffuse midline glioma (DMG), H3 K27-altered, is a newly defined \"pediatric-type,\" diffuse, high-grade glioma under current WHO classifications (updated in 2021). An essential diagnostic criteria of DMG is its occurrence in the midline structures; most intracranial DMG occurs in the brainstem or thalamus but can also occur in other midline structures. We experienced 2 adult cases of intracranial DMGs in areas other than the brainstem and thalamus that were initially difficult to diagnose. Case 1 was a 49-year-old man with extensive T2 high-signal lesions in the bilateral frontal lobes and corpus callosum on brain MRI. A Gd-based contrast medium partially enhanced the lesion and showed marked diffusion restriction, mimicking malignant lymphoma. Case 2 was a 24-year-old man who presented with paroxysmal olfactory abnormalities. The tumor extended mainly to the right temporal lobe, the right basal forebrain, and the bilateral hypothalamus, showing a T2/FLAIR mismatch sign suggestive of IDH-mutant astrocytoma without 1p/19q co-deletion. After a biopsy, both cases were properly diagnosed as DMG, H3 K27-altered (K27M-mutant). Diagnosing adult cases involving atypical midline structures is sometimes challenging before surgery; we discuss this phenomenon with both case details and a literature review.
摘要：
弥漫性中线胶质瘤（DMG），H3K27-改变，是一种新定义的“儿科类型”，\"弥漫，世卫组织目前分类下的高级别神经胶质瘤（2021年更新）。DMG的基本诊断标准是其在中线结构中的出现；大多数颅内DMG发生在脑干或丘脑中，但也可以发生在其他中线结构中。我们在脑干和丘脑以外的区域经历了2例成人颅内DMG，最初难以诊断。病例1是一名49岁的男性，在脑MRI上双侧额叶和call体具有广泛的T2高信号病变。基于Gd的造影剂部分增强了病变，并显示出明显的弥散限制，模仿恶性淋巴瘤.病例2是一名24岁的男性，他表现出阵发性嗅觉异常。肿瘤主要延伸到右颞叶,右基底前脑，和双侧下丘脑，显示T2/FLAIR错配标志，提示没有1p/19q共缺失的IDH突变型星形细胞瘤。活检后,这两个病例都被正确诊断为DMG，H3K27-改变（K27M-突变体）。在手术前诊断涉及非典型中线结构的成人病例有时具有挑战性；我们通过病例细节和文献综述来讨论这种现象。
