Abstract:
The World Health Organization classification of central nervous system neoplasms (2016 update) recognizes 4 histological variants and genetically defined molecular subgroups within medulloblastoma (MB). MB with myogenic differentiation is one of the rare variants, which is usually recognized as a pattern alongside the known histological variants. Because of its rarity, less is known about its molecular landscape and importantly about its placement in the current molecular schema. We aimed to analyze this rare variant for expression of 3 immunohistochemical markers conventionally used in molecular stratification of MB. Demographic profile and imaging details with survival outcome were also analyzed. Sixty-five MB cases were molecularly stratified using immunohistochemical markers (YAP1, GAB1, β-catenin). MB with myogenic differentiation and MB cases showing variable immunoreactivity with the above 3 antibodies were further evaluated for smooth muscle actin, desmin, myogenin, and HMB45. Seven cases were categorized as MB with myogenic and/or melanotic differentiation. Age ranged from 2 to 40 years with a male-to-female ratio of 1:1.3. In 4 cases, myogenic or melanotic differentiation was evident on histology, whereas in 3, differentiation was highlighted only with muscle markers. Interestingly, all 7 cases showed variable immunoreactivity with 3 molecular markers and did not follow the conventionally accepted algorithm used for molecular stratification. Follow-up period ranged from 9 to 57 months. Overall survival revealed a varied pattern, with 3 deaths and 4 patients being alive with no evidence of disease at last follow-up. Our results provide evidence that these variants are distinct and do not align immunohistochemically with the currently recognized genetic subgroups.
摘要:
世界卫生组织对中枢神经系统肿瘤的分类(2016年更新)识别了髓母细胞瘤(MB)中的4种组织学变异和遗传定义的分子亚群。具有肌源性分化的MB是一种罕见的变异,通常与已知的组织学变异一起被认为是一种模式。因为它的稀有性,对它的分子景观知之甚少,重要的是对它在当前分子模式中的位置知之甚少。我们旨在分析这种罕见的变体,以表达常规用于MB分子分层的3种免疫组织化学标记。还分析了人口统计学特征和影像学细节以及生存结果。使用免疫组织化学标记(YAP1,GAB1,β-catenin)对65例MB病例进行分子分层。进一步评估具有肌源性分化的MB和显示与上述3种抗体的可变免疫反应性的MB病例的平滑肌肌动蛋白,desmin,Myogenin,HMB457例被归类为具有肌源性和/或黑色素分化的MB。年龄为2至40岁,男女比例为1:1.3。在4个案例中,肌源性或黑色素分化在组织学上很明显,而在3中,分化仅在肌肉标记中突出显示。有趣的是,所有7例病例均显示3种分子标志物的免疫反应性不同,且未遵循常规接受的分子分层算法.随访期为9~57个月。总体生存率显示出不同的模式,3例死亡和4例患者在最后一次随访中没有疾病迹象。我们的结果提供了证据,表明这些变异是不同的,并且在免疫组织化学上与目前公认的遗传亚组不一致。