BACKGROUND Pleomorphic xanthoastrocytoma (PXA) is a rare astrocytic glioma, characterized by large pleomorphic and frequently multinucleated cells, spindle and lipidized cells, a dense pericellular reticulin network, and numerous eosinophilic granular bodies according to the grade II glial tumor standards of the World Health Organization's (WHO) 2016 guidelines. PXA rarely transforms into anaplastic PXA or glioblastoma (GBM) and anaplastic PXA, classified as WHO grade III, has a more aggressive clinical behavior with poorer prognosis than PXA. CASE PRESENTATION Here we describe an unusual case of PXA in a 19-year-old woman, first admitted with headache and a mass in the left temporal lobe in 2005 that was removed. Twelve years later, she returned with left temporal headache, diplopia and tinnitus. A local tumor recurrence was found, and a second resection was performed. The specimen showed highly malignant findings, such as necrosis, microvascular proliferation, and multiple mitoses. The integrated diagnosis was made as high grade glioma, probably derived from PXA. Immunohistochemical (IHC) stains were positive for oligo2, and approximately 21% positive for Ki-67, while negative for CD34, IDH1 R132H. INI1 and ATRX were retained. As the histological classification was glioblastoma, the patient received GBM-appropriate chemotherapy and radiation therapy and outpatient follow-ups have demonstrated no obvious symptoms for 1 year after surgery. Additional molecular analyses found BRAF V600E mutations in both resections, supporting the idea that the recurrent tumor had derived from PXA. CONCLUSIONS This case highlights the complexities of differential diagnosis based on the World Health Organization's 2016 guidelines. More integrated criteria to differentiate anaplastic PXA from GBM and epithelioid GBM, combined with genetic screening results, might be needed.

中文翻译：

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多形性黄体星形细胞瘤恶变及鉴别诊断：病例报告。

背景多形性黄体星形细胞瘤（PXA）是一种罕见的星形细胞胶质瘤，其特征是根据世界卫生组织的II级神经胶质肿瘤标准，大型多形性且经常为多核的细胞，纺锤形和脂化细胞，致密的周质网网络以及众多的嗜酸性粒状体。 （WHO）2016指南。PXA很少转变为间变性PXA或胶质母细胞瘤（GBM），而间变性PXA被列为WHO III级，其临床行为比PXA更具侵略性，预后较差。病例介绍在这里，我们描述了一名19岁女性中不寻常的PXA病例，该患者于2005年首次因头痛入院，左侧颞叶有肿块被切除。十二年后，她因左颞部头痛，复视和耳鸣而返回。发现局部肿瘤复发，然后进行第二次切除。标本显示出高度恶性的发现，例如坏死，微血管增生和多个有丝分裂。综合诊断为高度恶性胶质瘤，可能源自PXA。免疫组织化学（IHC）染色oligo2阳性，Ki-67阳性约21％，而CD34，IDH1 R132H阴性。INI1和ATRX被保留。由于组织学分类为胶质母细胞瘤，因此该患者接受了GBM合适的化学疗法和放射疗法，并且门诊随访显示术后1年没有明显症状。进一步的分子分析在两个切除部位均发现了BRAF V600E突变，支持了复发性肿瘤源自PXA的观点。结论本案例强调了基于世界卫生组织2016年指南的鉴别诊断的复杂性。可能需要更综合的标准来区分间变性PXA与GBM和上皮样GBM，并结合基因筛查结果。