Ono Takahiro, Takahashi Masataka, Hatakeyama Junya, Oda Masaya, Sahm Felix, Nanjo Hiroshi, von Deimling Andreas, Shimizu Hiroaki
Department of Neurosurgery, Akita University Graduate School of Medicine, Akita, Akita, Japan.
Department of Neuropathology, Institute of Pathology, Heidelberg University Hospital, Heidelberg, Germany.
NMC Case Rep J. 2019 Jun 5;6(3):95-99. doi: 10.2176/nmccrj.cr.2018-0282. eCollection 2019 Aug.
This paper reports on a case of pilocytic astrocytoma (PA), for which a diagnosis by conventional pathological diagnosis was difficult but an accurate diagnosis was possible by a new molecular diagnostic method. A 13-year-old girl whose tumor developed by a headache that gradually worsened, and a well-demarcated T-hyperintense lesion was found in the left cerebellum by a magnetic resonance imaging while the apparent diffusion coefficient value was also high. While the finding was a typical PA, histological features of PA were not found in the surgical specimen. An initial diagnosis was anaplastic astrocytoma (AA), and the final diagnosis through a central review was diffuse astrocytoma (DA). On the other hand, using MethylationEPIC (850 K) array, an analysis by a DNA methylation-based tumor classifier tool as reported by Capper et al. showed that this case belonged to a methylation class of PA. The copy number profile calculated from the methylation array data showed hints of BRAF/KIAA1549 fusion and no other chromosomal alterations, which also supported the molecular diagnosis. The patient was treated with local radiotherapy concomitant with temozolomide based on the initial pathological diagnosis during the consultation, but maintenance temozolomide therapy was not done according to the final molecular diagnosis. The tumor showed no recurrence for 20 months. In this case, the integrated diagnostic approach based on histological and molecular findings was clinically significant to select proper adjuvant treatment. It is crucial that the usefulness and robustness of this new molecular diagnostic method be validated further.
本文报道了一例毛细胞型星形细胞瘤（PA），该病例通过传统病理诊断难以确诊，但采用一种新的分子诊断方法可实现准确诊断。一名13岁女孩因头痛逐渐加重而发现肿瘤，磁共振成像显示左小脑有一个边界清晰的T2高信号病变，表观扩散系数值也较高。虽然该表现为典型的PA，但手术标本中未发现PA的组织学特征。初步诊断为间变性星形细胞瘤（AA），经中心复审最终诊断为弥漫性星形细胞瘤（DA）。另一方面，使用甲基化EPIC（850K）芯片，采用Capper等人报道的基于DNA甲基化的肿瘤分类工具进行分析，结果显示该病例属于PA的甲基化类别。从甲基化芯片数据计算得出的拷贝数图谱显示有BRAF/KIAA1549融合的迹象，且无其他染色体改变，这也支持了分子诊断。在会诊期间，根据初步病理诊断，患者接受了局部放疗联合替莫唑胺治疗，但根据最终分子诊断未进行替莫唑胺维持治疗。肿瘤20个月未复发。在该病例中，基于组织学和分子结果的综合诊断方法对于选择合适的辅助治疗具有临床意义。进一步验证这种新分子诊断方法的有效性和稳健性至关重要。
