1Department of Pathology, The Children's Memorial Health Institute, Polish Academy of Sciences, 5 Pawinskiego Str., 02-106 Warsaw, Poland.
Folia Neuropathol. 2009;47(4):354-61.
Ependymomas are relatively rare neoplasms of the central nervous system that typically develop along cerebral ventricles and central canal of spinal cord. Occasionally, the tumours of ependymal origin arise supratentorially in brain parenchyma as ectopic cortical mass without any connection to the ventricular system. Ependymomas are heterogeneous group of tumours including cellular, papillary, clear cell and tanacytic histology. The papillary ependymoma is an unusual variant of ependymoma characterized by distinct morphology resembling other papillary tumours and corresponding to WHO grade II malignancy. We present an unique case of ependymoma with distinctive papillary morphology at ectopic superficial cortical localization. The tumour occurred in eleven-years-old girl as a large, well-circumscribed mass in the left parietal lobe without continuity with the ventricular system. The patient presented with severe headache, vomiting and sudden-onset right hemiparesis. Histopathologically, the tumour revealed distinct papillary pattern with numerous pseudorosettes. Immunohistochemically, the neoplastic cells of both papillary structures and pseudorosettes were positive for glial fibrillary acidic protein and vimentin, whereas they were only slightly immunoreactive for epithelial membrane antigen and negative for cytokeratins. Ultrastructural findings revealed the presence of cilia usually located in the neoplastic cell bodies and intermediate glial-like filaments. The final diagnosis of papillary ependymoma at ectopic superficial localization was based on both, immunophenotypic profile and ultrastructural features that confirmed ependymal nature of neoplastic cells.
室管膜瘤是一种相对罕见的中枢神经系统肿瘤，通常沿着脑室内和脊髓中央管发展。偶尔，起源于室管膜的肿瘤会在脑实质中作为异位皮质肿块出现，与脑室系统没有任何联系。室管膜瘤是一组异质性肿瘤，包括细胞型、乳头型、透明细胞型和 tanacytic 组织学类型。乳头状室管膜瘤是一种不常见的室管膜瘤变异型，其特征是形态独特，类似于其他乳头状肿瘤，对应于 WHO 分级 II 恶性肿瘤。我们提出了一个独特的病例，即异位浅表皮质定位的具有独特乳头状形态的室管膜瘤。该肿瘤发生在 11 岁女孩身上，位于左顶叶，呈大而边界清楚的肿块，与脑室系统无连续性。患者表现为严重头痛、呕吐和突发性右侧偏瘫。组织病理学上，肿瘤显示出明显的乳头状模式，有许多假玫瑰花结。免疫组织化学染色显示，两种乳头状结构和假玫瑰花结的肿瘤细胞均对胶质纤维酸性蛋白和波形蛋白呈阳性反应，而对上皮膜抗原的反应仅轻微，对细胞角蛋白呈阴性。超微结构发现存在通常位于肿瘤细胞体和中间胶质样纤维中的纤毛。基于免疫表型特征和超微结构特征，最终诊断为异位浅表定位的乳头状室管膜瘤，证实了肿瘤细胞的室管膜起源。
