良性脊索细胞瘤临床病理观察

Benign notochordal cell tumour: a clinicopathological analysis

目的探讨良性脊索细胞瘤(BNCT)的临床病理特征、诊断与鉴别诊断。方法在临床资料及影像学所见基础上,分析1例BNCT的组织病理特征并复习相关文献。结果患者女性,48岁。下腰痛1年。CT扫描显示第4腰椎椎体软骨终板下占位性病变,具有清楚的硬化边,但无明显的皮质塌陷及骨质破坏。MRI示T2WI呈高信号,而T2WI呈低信号。行病灶彻底刮除及腰椎重建术。巨检:病变呈果冻样或貌似变性的骨髓脂肪。镜检:肿瘤主要由实性片层状脂肪样细胞或洋葱皮样细胞构成,肿瘤细胞马赛克样排列,胞膜清晰,胞质空泡状、泛白或轻度嗜酸性,核圆形、卵圆形,居中或偏位。不仅无显著的核异型及核分裂,同时缺乏分叶状结构、细胞外黏液样基质及丰富的血管网,也无松质骨浸润及坏死。病变中可见一些岛状分布的非肿瘤性骨髓组织。受累骨小梁硬化。免疫组化示CKpan和CK8/18(+),但CD68(-)。结论 BNCT是一种罕见的骨内脊索源性良性肿瘤,预后良好。

Objective To explore the chnicopathological features, diagnosis and differential diagnosis of benign notochordal cell tumor （BNCT）. Methods Based on clinical manifestations and imageological findings, one case of BNCT was analyzed by light microscopy and immunohistochemical study. And the relevant literature was reviewed. Results A 49-year-old woman who complained of mild lower back pain about one year was admitted to the hospital. CT scan revealed an occupied lesion beneath the cartilaginous endplate with well-defined and sclerotic boundary on the 4th vertebral body without apparent cortical disruption or bone destruction. MRI examination showed hyperintensity on T2WI and hypointense on T1WI. Then, she underwent a full curettage and lumbar reconstruction. Grossly, the mass was described as a jelly-like or degenerative fatty marrow appearance. Microscopically, the neoplasm composed predominantly of solid sheets of adipocyte-like or onion-like cells. It arranged in a mosaic pattern with distinct membranes, vacuolated, bland or lightly eosinophilic cytoplasm and eccentrically or centrally located round or polygonal nuclei. And the tumor cells presened with not only lacking of significant nuclear atypia or mitotic figures, but also lacking of lobulation, intercellular myxoid matrix and apparent vascular network. Furthermore, it had no permeative pattern or infiltrative growth in the cancellous bone and necrosis. Some islands of non-neoplastic hematopoietic bone marrow were seen. Meanwhile, the affected sclerotic trabeculae were observed in the lesion. Immunohistochemically, the tumor cell was positive for CKpan, CK8/18, but negative for CD68. Conclusion BNCT is a rare benign, intraosseous lesion of notochord origin. Full understanding the pathologic characteristics of the tumor is helpful to make a correct diagnosis.