成人幕上原始神经外胚层肿瘤的MRI表现及病理特点分析

Analysis of MRI Manifestations and Pathological Features in Adult Supratentorial Primitive Neuroectodermal Tumors

目的探讨成人幕上原始神经外胚层肿瘤(SPNET)的MRI表现与病理联系,提高诊断水平。方法搜集10例经手术病理证实的成人SPNET的临床病理及MRI资料,回顾性分析其影像学特点,并结合病理归纳其联系。男女比例为7∶3,中位年龄45.0岁,7例以头痛、呕吐首发,2例头痛伴晕厥,1例面部及舌根部麻木。均采用GE 1.5 T MRI扫描仪行MRI平扫+增强检查。结果病灶均单发,其中额叶5例、颞叶3例、顶叶2例,1例累及胼胝体膝部,无一例术前发生转移。病灶体积大,边界清,占位效应显著,3例无水肿,5例伴轻度水肿,2例伴明显水肿,2例伴出血,未见钙化。囊实性为主6例,表现为大囊小结节,壁结节多位于大脑凸面,囊变常靠近中线,实性为主4例,可伴灶性坏死,MRI上呈等或低T1WI、高或稍高T2WI信号,增强后呈"印戒"样或"蜂窝"样强化。结论成人SPNET的MRI表现与组织学特点密切相关,MRI表现具有特征性,仍依靠病理学确诊。

Objective To investigate the relationship between MRI features and pathologic findings in adult supratento- rial primitive neuroectodermal tumor （SPNET） in order to improve its diagnostic level. Methods A total of 10 patients with pathologically proved SPNET were included in this study. The clinical, pathological and MRI materials were collected. The imaging characteristics of SPNET were retrospectively analyzed. The correlation between imaging features and patholog- ical results were evaluated. The male-to-female ratio was 7：3 ; and the median age was 45.0 years. Clinical manifestations included headache and vomiting episode （ n = 7 ）, headache associated with syncope （ n = 2）, and numbness of face and tongue （ n = 1 ）. Both plain and contrast-enhanced MRI scans with a GE 1.5T MRI scanner were performed in all patients. Results Solitary lesion was seen in all patients. The lesions were located at the frontal lobe （ n = 5 ）, temporal lobe （ n = 3 ） and parietal lobe （ n = 2） with involvement of corpus callosum in one case. Before operation no metastasis was detected. The lesions were larger in size with a sharp border and obvious space-occupying effect. No edema was observed in 3 cases,mild edema was seen in 5 cases and notable edema in 2 cases; bleeding was found in 2 cases, while no calcification was seen. Cystic-solid lesion was found in 6 cases, presenting as a large cyst with small nodules; the nodules were usually located on the cerebral convexity and the cyst was very close to the midline. Solid lesion was seen in 4 cases, focal necrosis was accompanied in some cases, which was characterized by hypointensity or isointensity signals on T1WI and slight hyperintensity or hyperintensity signals on T2WI, and presented ＂signet ring＂ or ＂honeycomb＂ enhancement after contrast injection. Conclusion The MRI characteristics of adult SPNET are closely related to its pathological features. Although adult supratentorial primitive neuralectoderm tumors have certain MRI features, the confirmation of the diagnosis still depends on patholozical examination.