Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of notochordal tumors. Methods: The clinical, radiologic and pathologic data of 48 notochordal tumors were collected from 2008 to 2019 at Shanghai Jiaotong University Sixth People's Hospital. Expression of cytokertin, S-100 protein, vimentin, brachyury and INI1 was detected by immunohistochemistry. The pathologic differential diagnoses and biologic behavior of various types of notochordal tumors were analyzed using the new standard in the 5th edition of WHO tumor classification. Results: Four cases of benign notochordal cell tumor were confined to vertebral body. Histopathologically, they lacked lobular architecture and extracellular myxoid matrix. The tumor cells were vacuolated and had centrally or peripherally located round to oval nuclei, with small nucleoli, without atypia, mimicking mature adipocytes. No mitotic figures were seen. Two cases of poorly differentiated chordoma, from patients aged 12 years and 21 years respectively, were located in cervical vertebra, and were composed of cohesive sheets or nests of epithelioid cells, with focal rhabdoid morphology. There was relatively abundant eosinophilic cytoplasm and scattered cytoplasmic vacuoles. The moderately pleomorphic nuclei were round to ovoid with vesicular chromatin and mitotic figures could be seen. Extracellular myxoid stroma was observed focally. Forty cases of conventional chordoma and two cases of extra-axis chordoma had similar histologic features. All 48 cases expressed cytokeretin, 45 cases expressed brachyury, and two poorly differentiated tumors showed loss of INI1/SMARCB1. Conclusions: There are four subtypes of chordomas: conventional, dedifferentiated, poorly differentiated and extra-axis. Chondroid chordoma is no longer thought to be a distinct entity. Each type has its unique clinicopathological characteristics. Brachyury is highly specific and sensitive for the diagnosis of various notochordal tumors. Poorly differentiated chordoma shows distinct clinicopathological features, including young age and loss of immunohistochemical expression of INI1/SMARCB1, and its diagnosis requires the combined detection of brachyury and INI1/SMARCB1.
目的： 探讨不同类型脊索肿瘤的临床病理特征及其诊断、鉴别诊断。 方法： 收集2008—2019年间上海交通大学附属第六人民医院病理科诊断的48例脊索肿瘤临床、影像及病理资料，免疫组织化学做广谱细胞角蛋白（CKpan）、S-100蛋白、波形蛋白、Brachyury和INI1检测，结合第5版WHO骨和软组织肿瘤分类新标准，分析各型脊索肿瘤的病理鉴别诊断和生物学行为的差异。 结果： 4例良性脊索细胞瘤，均限于椎体内，镜下为骨小梁间片状分布的空泡状脂肪样细胞，边界清楚，胞质透明，细胞核中位或偏位，无异型，未见核分裂象；无细胞外黏液基质，缺乏分叶状结构。2例差分化亚型，年龄分别为12岁和21岁，均位于颈椎；肿瘤细胞呈片状分布，无明显的分叶结构，胞质嗜酸性，部分细胞呈横纹肌样，偶见小的空泡状细胞。核圆形或卵圆形，有中度异型，可见核分裂象。局灶区域见细胞外黏液。40例经典型脊索瘤，影像学均呈溶骨性骨质破坏，并累及骨旁软组织；有分叶结构，丰富的黏液样基质，片状或条索状排列的上皮样肿瘤细胞，胞质呈空泡状或嗜酸性；核有异型和核分裂；侵及周围软组织。2例中轴骨外脊索瘤，镜下结构类似经典型脊索瘤。48例全部表达CKpan，45例表达Brachyury，2例差分化亚型INI1/SMARCB1表达缺失。 结论： 脊索肿瘤包括良性的脊索细胞瘤和恶性的脊索瘤两大类，脊索瘤有经典型、去分化、差分化和中轴骨外4种亚型，软骨样脊索瘤不是独立的组织学亚型。各型脊索瘤有独特的临床病理特征。Brachyury对各型脊索肿瘤的诊断有高度特异度和灵敏度。好发于儿童和青少年的差分化脊索瘤形态特殊，需Brachyury和INI1/SMARCB1联合检测进行鉴别诊断。.