Zhang Xiu-Peng, Liu Yang, Zhang Di, Zheng Qin, Wang Chen, Wang Liang, Li Qing-Chang, Qiu Xue-Shan, Wang En-Hua
Department of Pathology, the First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, 110001, China.
Institute of Pathology and Pathophysiology, China Medical University, Shenyang, 110001, China.
Diagn Pathol. 2017 Mar 20;12(1):28. doi: 10.1186/s13000-017-0619-2.
Imaging and histology of clear-cell ependymoma and cerebellum-based hemangioblastoma are similar; distinguishing between them is a diagnostic challenge.
A 62-year-old Chinese woman presented with an intermittent headache of 8 years' duration. Computed tomography and magnetic resonance imaging revealed a mass in the cerebellum. Neurological imaging suggested hemangioblastoma (HB). Histologically, the tumor included cellular and paucicellular areas, in which cells were arranged in nests or diffusely distributed; and a highly vascular area, in which tumor cells were arranged in clusters and separated by capillaries. At low magnification, the tumor mimicked cellular HB, but at high magnification, tumor cells showed clear cytoplasm instead of the vacuolated cytoplasm typically observed in HB. Moreover, spindly, bipolar elements resembling tanycytes were observed within the nest structures. Although these features indicated the possibility of ependymoma, neither true ependymal rosettes nor an ependymal-lined profile was observed. The tumor was characterized by prominent vascularity, but glomeruloid formation was absent. We saw pleomorphism in foci of some tumor giant cells, but pathologic mitosis and palisaded necrosis were absent. Most tumor cells were positive for glial fibrillary acidic protein and S100. Epithelial membrane antigen was expressed with a paranuclear dot-like or a ring-like pattern. The Ki-67 index was approximately 2%. Considering the patient's symptom, neurological imaging, and pathological findings, she was diagnosed as cerebellar ependymoma (WHO grade II).
Here, we report a case of ependymoma with overlapping clear-cell and tanycytic features, and review the literature to evaluate its real incidence. Pathologists should consider this rare diagnosis when confronted with a similar presentation.
透明细胞室管膜瘤和小脑型血管母细胞瘤的影像学表现和组织学特征相似，鉴别二者具有诊断挑战性。
一名62岁中国女性，有8年间歇性头痛病史。计算机断层扫描和磁共振成像显示小脑有一肿块。神经影像学检查提示为血管母细胞瘤（HB）。组织学上，肿瘤包括细胞丰富区和细胞稀少区，细胞呈巢状排列或弥漫分布；以及一个血管高度丰富区，肿瘤细胞成簇排列，被毛细血管分隔。低倍镜下，肿瘤类似细胞型HB，但高倍镜下，肿瘤细胞显示透明细胞质，而非HB中典型的空泡状细胞质。此外，在巢状结构内观察到类似伸长细胞的梭形双极细胞成分。尽管这些特征提示可能为室管膜瘤，但未观察到真正的室管膜菊形团或室管膜内衬结构。肿瘤以显著血管化为特征，但无肾小球样形成。在一些肿瘤巨细胞灶中可见多形性，但无病理性核分裂和栅栏状坏死。大多数肿瘤细胞胶质纤维酸性蛋白和S100阳性。上皮膜抗原呈核旁点状或环状表达。Ki-67指数约为2%。综合患者症状、神经影像学和病理结果，诊断为小脑室管膜瘤（世界卫生组织二级）。
在此，我们报告一例具有透明细胞和伸长细胞特征重叠的室管膜瘤病例，并复习文献以评估其实际发病率。病理学家在面对类似表现时应考虑这一罕见诊断。
