Abstract:

Objective  To explore the clinical pathological characteristics, immunophenotyping, diagnosis and differential diagnosis and prognosis of pleomorphic xanthoastrocytoma (PXA) with anaplastic features.  Methods  HE staining was used for histological observation. The expressions of glial fibrillary acidic protein (GFAP), vimentin (Vim), CD34, epithelial membrane antigen (EMA), progestrone receptor (PR), neurofilment protein (NF), neuronal nuclei (NeuN), synaptophysin (Syn), Nestin (Nes), S-100 protein (S-100), P53 and Ki-67 labeling index were detected by immunohistochemical method. BRAF mutation was detected by polymerase chain reaction (PCR) amplification.  Results  A 43-year-old male patient presented with repeatedly paroxysmal tic of limbs and disturbance of consciousness. Cranial MRI revealed multiple abnormal signals in left temporo-occipito-parietal lobe and posterior horn of lateral ventricle, with unclear borderline and cystic degeneration. Surgical removal of the lesion was performed. Histologically, the tumor was biphasic. One part was composed of spindle cells arranged in fascicles or as running water, with weird multinuclear giant cells. Abundant vacuolated lipidized cytoplasm could be seen. Mitosis and "map"-like necrosis were noted. Another part revealed the tumor cells were consistent in size and uniform in distribution, with loose background tissue. Immunohistochemistry showed tumor cells were diffusely positive for GFAP, Vim, S-100, Nes, CD34 and P53, and negative for EMA, Syn, NeuN and NF. Ki-67 labeling index was about 15%. Reticular fiber staining showed abundant reticular fibers in the tumor tissue. BRAF mutation detected by PCR amplification was not found.  Conclusions  Classified as grade Ⅱ in the World Health Organization (WHO) classification, the prognosis of PXA is good. A diagnosis of PXA with anaplastic features should be considered when the tumor demonstrates mitotic activity > 5/10 high power field (HPF) and/or areas of necrosis. The differential diagnosis from glioblastoma multiforme and gaint cell glioblastoma should be paid attention, as all of them contain variable numbers of pleomorphic astrocytes, in order to avoid overtreatment.

Key words: Astrocytoma, Anaplasia, Pathology, Immunohistochemistry

摘要：

目的 探讨伴间变特征的多形性黄色瘤型星形细胞瘤的临床病理学特征、免疫表型、诊断与鉴别诊断要点及预后。方法与结果 男性患者，43 岁，表现为反复发作性四肢抽搐伴意识障碍，头部MRI 显示左侧颞顶枕叶、侧脑室后角旁多发异常信号，边界欠清晰，伴囊性变。手术全切除病灶。部分肿瘤细胞以梭形细胞为主，呈束状或流水样排列，其间可见怪异的多核瘤巨细胞，细胞内类脂空泡形成，核分裂象易见，局部可见“地图”样坏死；另一部分肿瘤细胞形态较一致，分布均匀、背景组织疏松。两种肿瘤成分均弥漫性表达胶质纤维酸性蛋白、波形蛋白、S-100 蛋白、巢蛋白、CD34 和P53，Ki-67 抗原标记指数约为15%；网状纤维染色肿瘤组织中可见大量网状纤维。BRAF 基因检测呈阴性。结论 对于多形性黄色瘤型星形细胞瘤核分裂象> 5/10 个高倍视野并伴坏死者，应考虑发生间变，注意与多形性和巨细胞型胶质母细胞瘤相鉴别，以免造成过度治疗。

关键词: 星形细胞瘤, 间变, 病理学, 免疫组织化学