Lach B, Benoit B G
Department of Pathology and Laboratory Medicine, Ottawa Civic Hospital, Ontario, Canada.
Ultrastruct Pathol. 2000 Sep-Oct;24(5):339-46.
The authors describe a primary sarcoma of the brain with immunohistochemical and ultrastructural features of leiomyosarcoma as well as epithelioid hemangiosarcoma. The leiomyosarcomatous component consisted of spindle cells with well-developed external lamina, subsarcolemmal densities composed of microfilaments, pinocytic vesicles, and abundant intermediate filaments, and showed immunohistochemical reactions for smooth muscle actin. The epithelioid part of the tumor contained scattered cells reactive for alkaline phosphatase as well as CD31 and factor VIII. Many epithelioid cells were lipidized and remarkably similar to "stromal cells" of a hemangioblastoma. Occasional Weibel-Palade bodies, indicating endothelial differentiation, were present in scattered neoplastic cells. There were also cells with features intermediate between endothelium, pericytes and smooth muscle cells, and undifferentiated mesenchymal cells. The brain at the periphery of sarcoma showed conglomerates of well-differentiated capillaries, telangiectasias and small dysplastic arteries, features that raise the possibility of origin of this tumor from a preexisting vascular developmental abnormality.
作者描述了一例原发性脑肉瘤，其具有平滑肌肉瘤以及上皮样血管肉瘤的免疫组化和超微结构特征。平滑肌肉瘤成分由梭形细胞组成，这些细胞具有发育良好的外板、由微丝构成的肌膜下致密物、吞饮小泡和丰富的中间丝，并显示出平滑肌肌动蛋白的免疫组化反应。肿瘤的上皮样部分含有散在的对碱性磷酸酶以及CD31和因子VIII呈反应性的细胞。许多上皮样细胞发生了脂质化，与成血管细胞瘤的“基质细胞”非常相似。散在的肿瘤细胞中偶见表明内皮分化的W-P小体。也存在具有介于内皮细胞、周细胞和平滑肌细胞之间特征的细胞以及未分化的间充质细胞。肉瘤周边的脑组织显示出分化良好的毛细血管团、毛细血管扩张和小的发育异常动脉，这些特征增加了该肿瘤起源于先前存在的血管发育异常的可能性。
