20例心房粘液瘤中,17例肿块位于左房,其中1例具低度恶性,光镜下部分瘤细胞呈腺体状排列,并浸润至心肌内;2倒位于右房;其余1例为病变累及左右心房的心房粘液肉瘤,亦属恶性。电镜检查除1例粘液肉瘤外,其余各例瘤细胞的超微结构基本相仿。瘤级织内含大量无定形基质,瘤细胞呈圆形、梭形或多角形,散在或成小群分布,其中部分为多核瘤巨细胞。瘤细胞表面富有胞质突起,相邻瘤细胞和 In 20 cases of atrial myxoma, 17 cases were located in the left atrium, of which 1 case had low grade malignancy. Some of the tumor cells were arranged in a glandular shape under the light microscope and infiltrated into the myocardium; 2 were located in the right atrium; Atrial lesions involving the atrial myxosarcoma, is also malignant. Electron microscopy in addition to a case of myxosarcoma, the rest of the cases of the basic ultrastructure of tumor cells are similar. Tumor-like tissue contains a large number of amorphous matrix, tumor cells were round, fusiform or polygonal, scattered or into small groups, some of which are multi-nuclear giant cells. The surface of tumor cells are rich in cytoplasm, adjacent tumor cells and