Dardick I, Hardie J, Thomas M J, van Nostrand A W
Department of Laboratory Medicine, Ottawa Civic Hospital, Ontario, Canada.
Head Neck. 1989 Jan-Feb;11(1):5-21. doi: 10.1002/hed.2880110104.
Ultrastructural studies of pleomorphic adenoma have shown a coordinated differentiation of luminal epithelial and modified myoepithelial cells with the latter cells related to processes resulting in the myxochondroid stroma. Five examples of various histologic types of malignant mixed tumor of parotid origin were examined by electron microscopy to see if underlying patterns of tumor cell differentiation and organization matched those of pleomorphic adenoma. Whether they were intracapsular tumors (with or without identifiable pleomorphic adenoma), carcinomas ex pleomorphic adenoma, or a true malignant mixed tumor, all lesions had cell types and organizations either identical to those in pleomorphic adenoma or, as in less-differentiated examples, displayed features suggesting origin from luminal cells, myoepithelial cells, or both. Even the chondroid cells in the true malignant mixed tumor expressed ultrastructural features indicating their epithelial derivation. On the basis of these findings, some alterations to the classification and terminology of the subtypes of malignant mixed tumor are suggested.
多形性腺瘤的超微结构研究显示，管腔上皮细胞和改良肌上皮细胞存在协调分化，后者与形成黏液软骨样基质的过程相关。对5例腮腺来源的不同组织学类型的恶性混合瘤进行了电子显微镜检查，以观察肿瘤细胞分化和组织的潜在模式是否与多形性腺瘤的模式相匹配。无论它们是包膜内肿瘤（有或无明确的多形性腺瘤）、多形性腺瘤恶变、还是真正的恶性混合瘤，所有病变的细胞类型和组织结构要么与多形性腺瘤中的相同，要么在分化程度较低的病例中，表现出提示起源于管腔细胞、肌上皮细胞或两者的特征。即使是真正的恶性混合瘤中的软骨样细胞也表现出超微结构特征，表明其上皮来源。基于这些发现，对恶性混合瘤亚型的分类和术语提出了一些修改建议。
