脊柱原始神经外胚层肿瘤的CT与MRI诊断

Spinal Primitive Neuroectodermal Tumors:CT and MRI Findings

目的探讨脊柱原始神经外胚层肿瘤(PNET)的CT及MRI特征,提高对本病的认识。资料与方法收集经手术病理证实的9例脊柱PNET,结合相关文献分析其影像学特征。结果 9例PNET肿块均呈中等密度,邻近椎体有不同程度的骨质破坏,6例见椎间孔扩大;9例肿块均位于髓外硬膜下,8例T1WI呈等或低信号,1例T1WI呈稍高信号,T2WI呈等、混杂、稍高信号,7例有囊变,9例均见早期明显强化;免疫组化结果显示9例均见CD99表达,5例神经元特异性烯醇酶表达,4例神经突触素表达,2例波形蛋白表达,1例上皮细胞膜抗原表达。结论脊柱PNET具有椎管内髓外硬膜下中等密度软组织肿块、易囊变、T1WI呈等或低信号、T2WI呈等或稍高信号、早期快速强化、沿椎间孔跨椎管内外生长并破坏相邻脊柱骨质的特征,对于出现上述CT与MRI特征、年龄较小、病史较短的患者应考虑脊柱PNET的可能,确诊依靠病理和免疫组化检查。

Purpose To analyze the CT and MRI findings of spinal primitive neuroectodermal tumors （PNET）, so as to know more about PNET. Materials and Methods The CT and MRI data of nine patients with spinal PNET confirmed pathologically by surgery were retrospectively studied together with the analysis of related literature. Results All the PNET tumors of nine patients presented moderate density, with adjacent vertebral bone destruction of different degrees, six of which were seen enlarged foramen intervertebrale. All were intradural extramedullary tumors, eight with iso- or hypointense and one with slight hyperintense on T1WI phase; the lesions demonstrated isointensity, heterogeneous, and slight hyperintense on T2WI phase. Seven cases had cystic change. All nine cases showed early enhancement. The immunohistochemical examination showed CD99 expression in all cases, five cases with neuron specific enolase expression, four with synaptophysin expression, two with vimentin expression and one with epithelial membrance antigen. Conclusion Spinal PNET shows moderate density, prone to cystic change, with iso- or hypointense on TIWI and iso- or slight hyperintense on T2WI, enhance rapidly in early stage, grow along the intervertebral foramen cross-section of infiltration or outside the spinal canal, and damage adjacent vertebral bone. Patients at young age with the above CT and MRI features and short medical history should consider this disease, but the final diagnosis depends on pathological and immunohistochemical examination.