The pathologic studies of oligodendrogliomas for the improvement of diagnostic accuracy.

虽然少突胶质瘤是一种常见的胶质瘤，但它经常与其他类型的肿瘤相混淆。为了选择合适的治疗方式，建立客观的诊断标准并提出正确诊断的有效方法是很重要的。我们使用FISH评估了少突胶质细胞瘤和其他类似物中1p丢失的频率。60%的少突胶质细胞瘤表现出缺失，而其他肿瘤则没有。然后，用免疫组织化学方法研究了少突胶质细胞和星形胶质细胞肿瘤中微管相关蛋白(微管相关蛋白，MAP-2)和少突胶质细胞系基因(Opol2)的表达。所有研究的蛋白在少突胶质细胞瘤中都有表达，但不是特异性的。用形态计量学方法比较少突胶质瘤和星形细胞瘤的细胞学特征。与星形细胞瘤相比，少突胶质细胞瘤的细胞核更圆、更规则。最后，1P丢失(+)和1P丢失(-)的少突胶质细胞瘤的超微结构特征没有差别。除了罕见的星形细胞或神经元分化的肿瘤细胞外，少突胶质细胞瘤主要由不典型的少突胶质细胞样细胞组成。根据定义标准，少突胶质细胞瘤目前应根据其特征性的显微镜特征来诊断。细胞学、免疫组织化学、电子显微镜和分子细胞遗传学等综合分析将提高诊断的准确性。尤其是后者对治疗决策具有重要意义。

Although it is a common glioma, oligodendroglioma is often confused with other types of tumors. For the selection of appropriate therapeutic modality, it is important to establish objective diagnostic criteria and to propose an effective approach for the correct diagnosis.We evaluated the frequency of 1p loss in oligodendrogliomas and other mimics using FISH. 60% of oligodendrogliomas showed the loss, but other tumors did not. This indicates that the loss of 1p is specific to oligodendrogliomas.Then, the expression of microtubule-related proteins (tubulin, MAP-2) and oligodendrocyte lineage gene (Olig2) was immunohistochemically studied in oligodendroglial and astrocytic tumors. All proteins studied were expressed in oligodendrogliomas, but they were not specific to them.Cytologic features of oligodendrogliomas were compared with those of astrocytomas using the morphometry. Nuclei of oligodendrogliomas were significantly rounder and more regular in shape than those of astrocytomas.Finally, the ultrastructural features were not different between 1p loss (+) oligodendrogliomas and 1p loss (-) ones. They were principally composed of nondescript, oligodendrocyte-like cells in addition to rare tumor cells that show astrocytic or neuronal differentiation.Following the definition criteria, oligodendrogliomas should currently be diagnosed based on the characteristic microscopic features. Comprehensive analyses including cytology, immunohistochemistry, electron microscopy and molecular cytogenetics will improve the diagnostic accuracy. Especially, the latter is important for the therapeutic decision.