中枢神经系统孤立性纤维性肿瘤／血管外皮瘤71例临床病理分析

Solitary fibrous tumor/hemangiopericytoma of central nervous system： a clinicopathologic analysis of 71 cases

目的由于中枢神经系统（CNS）孤立性纤维性肿瘤（SFT）与血管外皮瘤（HPC）的分子遗传学特征一致，2016 WHO CNS肿瘤分类将二者合为SFT/HPC，并分为3级。本文主要探讨CNS SFT/HPC的临床病理学特征、诊断、鉴别诊断及临床预后等。方法收集71例CNS SFT和HPC进行回顾性研究和重新分级，对组织形态学、免疫组织化学和临床影像资料进行分析，并进行随访及复习相关文献。结果71例患者中男性37例，女性34例；年龄3～77岁，中位年龄48岁。WHO Ⅰ级12例（17%）、WHOⅡ级26例（37%）和WHOⅢ级33例（46%）。镜下可表现为经典的SFT表型、HPC表型或二者混合。免疫表型上，97%（69/71）的病例表达STAT6，其中96%（66/69）的病例弥漫强阳性；bcl－2、CD99及波形蛋白表达率均约为90%；CD34表达率随着肿瘤级别升高而降低，平均表达率为78%，10%（7/71）的病例不同程度表达SSTR2a，其中1例胞质强阳性；极少数病例局灶表达上皮细胞膜抗原、CD57、S－100蛋白；Ki－67阳性指数1%～50%。34例随访8～130个月，其中12例复发（35%），2例（6%）发生肝转移。结论CNS SFT/HPC相对少见，不同级别之间临床病理和预后之间明显重叠或过渡。STAT6是目前诊断该肿瘤较为特异的标志物。手术切除为首选治疗手段，Ⅱ级和Ⅲ级易复发及转移，最常转移部位为肝脏。

ObjectiveAs solitary fibrous tumor （SFT） and hemangiopericytoma （HPC） share the same molecular genetics features, the 2016 WHO classification of central nervous system （CNS） tumors had created the combined term SFT/HPC and assigns three grades. This study aims to investigate the clinicopathologic characteristics, diagnosis, differential diagnosis and prognosis of CNS SFT/HPC. MethodsSeventy-one cases of CNS SFT and HPC were retrospectively reclassified and studied. Histopathological, immunohistochemical and imaging features were analyzed. The follow-up data were analyzed.ResultsThere were 37 male and 34 female patients. The median age was 48 years （range, 3-77 years）. Twelve cases （17%） were WHO grade Ⅰ, 26 （37%） were WHO grade Ⅱ and 33 （46%） were WHO grade Ⅲ. Microscopically the tumor could show traditional SFT phenotype, HPC phenotype or mixed phenotype. Immunochemically, 97%（69/71） were positive for STAT6, with 96%（66/69）showing diffuse strong staining. Approximately 90% were diffusely positive for bcl-2, CD99 and vimentin. The expression rate of CD34 decreased with increasing tumor grade, and the mean expression rate was 78%. SSTR2a was variably expressed in 10% （7/71） of cases including one case showing strong cytoplasmic staining. A few cases expressed EMA, CD57 and S-100 focally. The Ki-67 index ranged from 1% to 50%. Thirty four patients were followed up for 8-130 months; 12 patients（35%）had recurrences, and two （6%） had liver metastases.ConclusionsCNS SFT/HPC is relatively uncommon. There was significant morphological overlap or transition between different grades. STAT6 is a specific marker for the diagnosis of this tumor. Surgical resection is the preferred treatment. WHO grade Ⅱ and Ⅲ SFT/HPC show rates of local recurrence and systemic metastasis, with liver being the most common site of extracranial metastasis.