胚胎发育不良性神经上皮瘤临床病理观察

A clinicopathologic study of dysembryoplastic neuroepithelial tumor

目的研究胚胎发育不良性神经上皮瘤(DNT)的临床表现、影像学特点、病理组织学特征及治疗和预后。方法应用光镜、电镜及免疫组织化学染色方法(SP法)对18例DNT进行观察分析,并对其中14例进行了随访。结果患者年龄3～46岁,平均年龄22.8岁,男14例,女4例,主要症状为顽固性癫痫发作,术前癫痫病史最长达17年。MRI检查示病灶T1WI呈低信号,T2WI呈高信号,肿瘤周围无水肿及占位效应。18例肿瘤除2例位于小脑外,其余均位于大脑皮质。本组全切除者10例,大部切除者8例。随访14例,13例生存者中,生存1年4个月～11年,平均已生存5.5年,其中已生存10年以上者2例。术后无1例复发。肿瘤呈结节状分布于大脑或小脑的皮质内,部分累及白质。“特异性胶质神经元成分”为DNT病理形态学特征,是由不同比例的少突胶质细胞样细胞(OLC)、成熟神经元和星形细胞组成,肿瘤有明显的微囊变,单个神经元漂浮在微囊的黏液样基质中,本病多伴有肿瘤周围脑皮质发育不良。免疫组织化学染色示神经元及部分OLC突触素、神经微丝及S100染色阳性,OLC胶质纤维酸性蛋白染色阴性。电镜示OLC有早期神经元分化、星形细胞分化及少突胶质细胞分化。结论DNT属良性肿瘤(WHOⅠ级),手术切除即可治愈。应结合临床表现、影像学及病理组织学和免疫组织化学结果确诊DNT。

Objective To study the clinicopathologic features, radiologic findings, treatment modalities and prognosis of dysembryoplastic neuroepithelial tumor （DNT）. Methods The clinical features, histopathologic findings, immunohistochemistry and electron microscopy of 18 cases of DNT were analyzed. Results Among the 18 cases studied, 14 were males and 4 females. The age of these patients ranged from 3 to 46 （mean age = 22. 8 years ）. Partial seizure was the main presenting symptom in all patients. The history of epilepsy could be as long as 17 years. On magnetic resonance imaging （ MRI ） study, the tumor was hypodense on T1 and hyperdense on T2. There was neither edema nor mass effect. All but 2 cases were supratentorial and intracortical in location. Ten cases were treated by complete surgical excision and the remaining 8 tumors were partially excised. In the 14 patients with follow-up data available, 13 survived for 1.4 to 11 years after the operation （with more than 10 years survival observed in 2 patients）. The average survival period was 5.5 years. None of the cases showed tumor recurrence after operation. Histologically, all tumors demonstrated a muhinodular architecture and were intracortical in location, sometimes with extension into the white matter. The characteristic “ glioneuronal constituent” was an essential feature for making the diagnosis of DNT. The tumor was formed by an admixture of oligodendrocyte-like cells, mature neurons and astrocytes, with obvious microcystic changes. These neurons were often dispersed singly in the mucoid matrix. In most cases, the foci of cortical dysplasia were found in adjacent areas. Immunohistochemical study demonstrated positivity for synaptophysin, neurofilament and S-100 protein in the neurons and some oligodendrocyte-like cells. The staining of glial fibrillary acidic protein in the oligodendrocyte-like cells was negative. Electron microscopy showed early neuronal, astrocytic and oligodendroglial differentiation of the oligodendrocyte-like cells. Conclusions DNT is a benign tumor （ corresponding to WHO grade I） that can be cured by surgical excision, despite sometimes incomplete tumor removal. A correct diagnosis of this entity requires thorough understanding of the clinical, radiologic, histologic and immunohistochemical features.