摘要目的 探讨INI1缺失的低分化脊索瘤的临床特点、影像学表现、病理学形态、免疫表型、分子病理特征及其鉴别诊断.方法 对2例INI1缺失的低分化脊索瘤的临床资料、影像学表现、病理学形态、免疫表型和分子病理特征进行回顾性分析.结果 2例均为儿童,1例女性,1例男性.病变部位均位于斜坡.患儿以进行性肌无力或颈部疼痛就诊.影像学示斜坡骨质异常伴占位性病变,脑干、颈髓显著受压改变.显微镜下肿瘤缺乏脊索瘤的典型组织形态,肿瘤细胞片状分布,细胞密集排列,瘤细胞呈卵圆形或梭形,细胞异型性明显,细胞核呈空泡状,核仁明显.免疫组织化学显示肿瘤细胞表达细胞角蛋白、上皮细胞膜抗原和brachyury,而S-100蛋白呈弱表达或部分表达,INI1表达缺失,Ki-67阳性指数均较高.荧光原位杂交(FISH)技术检测示2例肿瘤细胞均出现INI1基因缺失.结论 INI1缺失的低分化脊索瘤多发生于儿童,其组织形态异于普通脊索瘤,免疫组织化学及FISH检测示INI1缺失,brachyury可以帮助鉴别诊断.低分化脊索瘤的INI缺失可能与其低分化的组织形态和不良的预后相关.

abstractsObjective To analyze the clinicopathologic characteristics of poorly-differentiated chordoma with INI1 loss in children and to discuss the differential diagnosis. Methods The clinical, radiological, histopathological profiles and molecular pathologic characteristics of two pediatric poorly differentiated chordoma cases with INI1 loss were reviewed. Results The patients were a girl and a boy. Both lesions involved the slope. Both patients were presented with progressive muscle weakness or neck pain. Radiological examination showed clivus bone destruction and compression of the brain stem and cervical spinal cord. Histologically, the tumor cells lacked typical organization and were associated with inflammatory cells infiltration. On high power field, the tumor cells were ovoid or fusiform with prominent atypia, vacuolated nuclei and prominent nucleoli. By immunohistochemistry, the tumor cells expressed cytokeratin, epithelial membrane antigen, brachyury and were negative for INI1. In both cases, INI1 gene deletion was detected by FISH. Conclusions Poorly-differentiated chordoma with INI1 loss mainly occurs in children. The morphology is different from classical chordoma. INI1 gene deletion is detectable by FISH. It can be distinguished from atypical teratoid/rhabdoid tumors and other neoplasms by the identification of nuclear brachyury expression. The loss of INI1 expression in poorly-differentiated chordoma might be associated with a poorly-differentiated morphology and an adverse prognosis.