３７例原发骨恶性纤维组织细胞瘤（ＭＦＨ）中１２例原始诊断即为该病，余诊断为纤维肉瘤、骨巨细胞瘤或其他恶性瘤。骨ＭＦＨ多发生于长骨两端，以膝关节上、下多见，其组织学表现特征为肿瘤细胞成份多种多样和细胞排列方式复杂多变。用透射电镜观察几种主要的瘤细胞在超微结构上有一致性。５种抗体免疫组化染色中，α１－抗胰蛋白酶阳性率为７８％，α１－抗糜蛋白酶为７４％，可作为有鉴别意义的免疫标记物。 Among the 37 cases of primary malignant bone fibrous histiocytoma (MFH), the original diagnosis was 12 cases, and the rest were diagnosed as fibrosarcoma, giant cell tumor of bone, or other malignant tumors. Bone MFH occurs at both ends of long bones, and is commonly seen at upper and lower knee joints. Its histological features are diverse in tumor cell composition and complex and variable arrangement of cells. Transmission electron microscopy was used to observe the ultrastructural consistency of several major tumor cells. In the immunohistochemical staining of the five antibodies, the positive rate of α1-antitrypsin was 78%, and that of α1-antichymotrypsin was 74%. It can be used as a differential immunological marker.