Hendrix Joshua, Xiong Zhenggang
Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers University, NJ, USA.
Intractable Rare Dis Res. 2020 Nov;9(4):260-262. doi: 10.5582/irdr.2020.03088.
Pilocytic astrocytomas are tumors of the central nervous system mostly during the first two decades of life. Although they are mostly common in the midline structures of children, pilocytic astrocytoma within the ventricular system of an adult is extremely rare. We report a case of a 38-year old woman with obstructive hydrocephalus secondary to a brain tumor within the third ventricle. On histological examination, the tumor exhibited biphasic growth pattern comprising compacted cellular areas with Rosenthal fibers and loose textured microcystic areas with eosinophilic granular bodies. Mitosis or necrosis was not present. Immunohistochemical studies demonstrated glial fibrillary acid protein (GFAP), Olig2, and ATRX positivity as well as NeuN and EMA negativity. Ki67 labeling index was less than 1%. Molecular studies revealed that there are no isocitrate dehydrogenase () gene mutation and mutation. This clinical presentation along with the histologic and molecular findings is consistent with a pilocytic astrocytoma arising in the third ventricle of this adult brain, which indicates that pilocytic astrocytoma can present as an intraventricular tumor in an adult patient and should be routinely included in the differential diagnosis of intraventricular brain neoplasm.
毛细胞型星形细胞瘤是主要发生在生命最初二十年的中枢神经系统肿瘤。虽然它们在儿童的中线结构中最为常见，但成人心室系统内的毛细胞型星形细胞瘤极为罕见。我们报告一例38岁女性，因第三脑室内脑肿瘤继发梗阻性脑积水。组织学检查显示，肿瘤呈现双相生长模式，包括有罗斯enthal纤维的致密细胞区和有嗜酸性颗粒体的疏松微囊区。未见有丝分裂或坏死。免疫组织化学研究显示胶质纤维酸性蛋白（GFAP）、少突胶质细胞转录因子2（Olig2）和α地中海贫血/智力发育迟缓综合征X连锁基因（ATRX）呈阳性，神经元核抗原（NeuN）和上皮膜抗原（EMA）呈阴性。Ki67标记指数小于1%。分子研究显示，不存在异柠檬酸脱氢酶（）基因突变和 突变。这种临床表现以及组织学和分子学发现与该成人大脑第三脑室内发生的毛细胞型星形细胞瘤一致，这表明毛细胞型星形细胞瘤可在成年患者中表现为脑室内肿瘤，在脑室内脑肿瘤的鉴别诊断中应常规考虑。
