Neuropathology Service, Institute of Pathology, University of Bern, 3010 Bern, Switzerland.
Pathol Res Pract. 2010 Jul 15;206(7):493-8. doi: 10.1016/j.prp.2009.07.013. Epub 2009 Oct 22.
By analogy to gliosarcoma, the term "ependymosarcoma" has recently been coined to thematize the rare phenomenon of a malignant mesenchymal component arising within an ependymoma. We report on an example of this paradigm, involving tanycytic ependymoma as the host tumor in a 40-year-old female who underwent two tumor extirpation procedures at one-year interval. She first presented with severe headaches, and was seen by imaging to harbor a moderately enhancing mass 2.5cm in diameter at the rostral septum pellucidum accompanied by occlusive hydrocephalus. Microscopically, the tumor consisted of solid, wavy fascicles of elongated cells that were occasionally interrupted by vague perivascular pseudorosettes. Mitotic activity was absent, and less than 1% of nuclei immunoreacted for MIB-1. A histological diagnosis of tanycytic ependymoma (WHO grade II) was rendered, and no adjuvant therapy given. At recurrence, the lesion was 3.5cm in diameter, intensely enhancing, and had already seeded into the subarachnoid space. Histology showed a biphasic glial-sarcomatous architecture with remnants of the original ependymoma now displaying hypercellularity and atypical - yet not frankly anaplastic - features. The sarcomatous moiety consisted of spindle and epithelioid cells densely interwoven with reticulin fibers. While the ependymal component was GFAP and S100 protein positive, and featured punctate staining for EMA, none of these markers was expressed in the adjacent sarcoma. Instead, the latter reacted for vimentin and smooth muscle actin. To the best of our knowledge, this is the first documentation of tanycytic ependymoma undergoing malignant transformation, one driven by a highly anaplastic mesenchymal component, corresponding to "ependymosarcoma".
类比于胶质肉瘤，术语“室管膜肉瘤”最近被用来描述一种罕见现象，即在室管膜瘤内出现恶性间叶成分。我们报告了一个范例，涉及到 40 岁女性的室管膜瘤，她在一年的时间内接受了两次肿瘤切除手术。她最初表现为严重的头痛，并通过影像学检查发现颅透明隔有一个直径为 2.5 厘米的中度增强肿块，伴有闭塞性脑积水。显微镜下，肿瘤由波浪状的长形细胞束组成，偶尔被模糊的血管周围假玫瑰结打断。没有有丝分裂活动，小于 1%的核对 MIB-1 免疫反应阳性。组织学诊断为室管膜瘤（WHO 分级 II），未给予辅助治疗。复发时，病变直径为 3.5 厘米，强化明显，并已播散到蛛网膜下腔。组织学显示出双相胶质-肉瘤结构，原来的室管膜瘤现在显示出细胞增多和非典型但不明显的间变特征。肉瘤部分由梭形和上皮样细胞组成，与网状纤维紧密交织。虽然室管膜成分对 GFAP 和 S100 蛋白呈阳性，并且对 EMA 呈点状染色，但这些标志物在相邻的肉瘤中均不表达。相反，后者对波形蛋白和平滑肌肌动蛋白呈阳性反应。据我们所知，这是首例报道室管膜瘤发生恶性转化的病例，由高度间变的间叶成分驱动，对应于“室管膜肉瘤”。
