Guccion J G, Saini N
Laboratory Service, Department of Veterans Affairs Medical Center, Washington, DC 20422.
Ultrastruct Pathol. 1991 Mar-Apr;15(2):159-66. doi: 10.3109/01913129109016234.
Several unusual ultrastructural findings in two ependymomas are reported. In case 1, a grade I ependymoma of the fourth ventricle, there were rosettes, perivascular pseudorosettes, and tumor cells having unusual intracytoplasmic vacuoles by light microscopy. Ultrastructurally, these vacuoles were frequently microrosettes as well as scattered, degenerated cytoplasmic processes of tumor cells. The lumina of some of the microrosettes were bordered by abnormally long and malformed zonulae adherentiae. In case 2, a recurrent grade III ependymoma of the third ventricle, there were rosettes and perivascular pseudorosettes as well as more cellular and anaplastic areas by light microscopy. Ultrastructurally, the cytoplasmic processes of tumor cells in perivascular pseudorosettes contained frequent dense-core vesicles and occasional parallel arrays of microtubules. These structures do not occur in normal mammalian ependymal cells but do occur in the ependymal tanycyte, a related cell that is plentiful in the walls of the third ventricle. Thus some of the tumor cells of this third ventricle ependymoma appear to have differentiated as tanycytes.
报告了两例室管膜瘤中一些不寻常的超微结构发现。病例1为第四脑室的I级室管膜瘤，光镜下可见玫瑰花结、血管周围假玫瑰花结以及具有异常胞质内空泡的肿瘤细胞。超微结构上，这些空泡常为微玫瑰花结以及肿瘤细胞散在、退化的胞质突起。一些微玫瑰花结的管腔由异常长且形态异常的紧密连接所界定。病例2为第三脑室复发性III级室管膜瘤，光镜下可见玫瑰花结、血管周围假玫瑰花结以及更多细胞性和间变区域。超微结构上，血管周围假玫瑰花结中肿瘤细胞的胞质突起含有频繁出现的致密核心囊泡和偶尔的微管平行排列。这些结构在正常哺乳动物室管膜细胞中不出现，但在室管膜室管膜细胞中出现，室管膜室管膜细胞是一种相关细胞，在第三脑室壁中大量存在。因此，该第三脑室室管膜瘤的一些肿瘤细胞似乎已分化为室管膜室管膜细胞。
