Santino Samara F, Salles Débora, Stávale João N, Malinverni Andréa C M
Department of Pathology, Universidade Federal de São Paulo, Escola Paulista de Medicina, São Paulo, Brazil; Laboratory of Molecular and Experimental Pathology, Universidade Federal de São Paulo, Escola Paulista de Medicina, São Paulo, Brazil.
Department of Pathology, Universidade Federal de São Paulo, Escola Paulista de Medicina, São Paulo, Brazil; Laboratory of Molecular and Experimental Pathology, Universidade Federal de São Paulo, Escola Paulista de Medicina, São Paulo, Brazil.
Pathol Res Pract. 2023 Aug;248:154593. doi: 10.1016/j.prp.2023.154593. Epub 2023 Jun 7.
Pilocytic astrocytoma is a central nervous system tumor of slow growth, which represents 5 % of all gliomas and most often develops in the cerebellum (42-60 %), but can also arise in other neural areas, such as the optic pathway or hypothalamus (9-30 %); brainstem (9 %); spinal cord (2 %). In the pediatric population, this tumor is the second most common cause of neoplasms and, on the other hand, in adults, it is often rare, probably due to its aggressiveness in these individuals. Studies reveal that the origin of pilocytic astrocytoma is characterized by a fusion between the BRAF gene and the KIAA1549 locus, and the application of the immunohistochemistry technique for the analysis of BRAF protein expression can be a valuable tool for diagnostic purposes. Due to the relative rarity of this disease in adults, there are few publications on the most effective diagnostic and treatment strategies for this tumor. The general objective of this study was to analyze the histopathological and immunohistochemical characteristics of pilocytic astrocytoma in these patients. For this, a retrospective study of patients aged over 17 years with a diagnosis of pilocytic astrocytoma was carried out at the Department of Pathology of UNIFESP/EPM, from 1991 to 2015. In order to define BRAF positivity in the immunohistochemical analysis, at least three consecutive fields with more than 50 % immunostaining were used as criteria and, thus, it was inferred that the 7 cases analyzed were considered positive for the cytoplasmic marker BRAF V600E. Histopathological analysis associated with BRAF immunostaining is of paramount importance as a diagnostic method in these cases. However, future molecular studies will be necessary both for a better understanding of the aggressiveness and prognostic of this tumor and for research involving specific therapies for pilocytic astrocytoma in adults.
毛细胞型星形细胞瘤是一种生长缓慢的中枢神经系统肿瘤，占所有胶质瘤的5%，最常发生于小脑（42%-60%），但也可发生于其他神经区域，如视路或下丘脑（9%-30%）；脑干（9%）；脊髓（2%）。在儿童群体中，这种肿瘤是第二常见的肿瘤病因，而在成人中则较为罕见，这可能是由于其在这些个体中的侵袭性所致。研究表明，毛细胞型星形细胞瘤的起源特征是BRAF基因与KIAA1549位点融合，应用免疫组织化学技术分析BRAF蛋白表达可作为一种有价值的诊断工具。由于该疾病在成人中相对罕见，关于该肿瘤最有效的诊断和治疗策略的出版物较少。本研究的总体目标是分析这些患者毛细胞型星形细胞瘤的组织病理学和免疫组织化学特征。为此，1991年至2015年期间在圣若泽杜斯坎普斯联邦大学医学院病理学系对17岁以上诊断为毛细胞型星形细胞瘤的患者进行了一项回顾性研究。为了在免疫组织化学分析中确定BRAF阳性，至少三个连续视野免疫染色超过50%作为标准，因此推断分析的7例病例被认为细胞质标记物BRAF V600E呈阳性。在这些病例中，与BRAF免疫染色相关的组织病理学分析作为一种诊断方法至关重要。然而，未来的分子研究对于更好地理解该肿瘤的侵袭性和预后以及涉及成人毛细胞型星形细胞瘤特异性治疗的研究都是必要的。
