摘要：

目的 探讨发生于鞍区和鞍上的脑室外神经细胞瘤的临床病理学特征。方法 对1 例鞍区和鞍上脑室外神经细胞瘤患者的临床表现、影像学特征、组织学形态、免疫表型和分子遗传学特征进行回顾分析并复习相关文献。结果 女性患者，27 岁，临床表现为反复头痛伴双眼视物模糊5 个月。头部MRI显示鞍区和鞍上占位性病变，T₁WI呈等或低信号，T₂WI呈高或低混杂信号，扩散加权成像呈稍高信号，界限清晰，正常垂体结构显示不清。临床诊断为垂体腺瘤，行经鼻蝶入路垂体腺瘤切除术+ 脑脊液鼻漏修补术+ 视神经减压术，手术全切除肿瘤。组织学形态可见肿瘤细胞呈弥漫浸润性生长，部分区域可见神经毡背景；肿瘤细胞大小和形态相对一致，胞核圆形或卵圆形，染色质细腻深染，未见核分裂象。免疫组织化学染色可见肿瘤细胞胞核表达神经元核抗原和甲状腺转录因子-1，胞核和胞质表达钙视网膜蛋白，胞质表达突触素、嗜铬素A、上皮钙黏素和基质金属蛋白酶-9；胞核局灶性表达S-100 蛋白，胞质局灶性表达神经微丝蛋白、细胞角蛋白8 和波形蛋白；Ki-67 抗原标记指数约为3%。网织纤维染色呈阴性。基因检测可见肿瘤细胞无异柠檬酸脱氢酶基因突变，无1p/19q-共缺失。最终病理诊断为脑室外神经细胞瘤（WHOⅡ级）。结论 鞍区和鞍上脑室外神经细胞瘤临床极为罕见，组织学形态与发生于脑室的中枢神经细胞瘤相似，表现为肿瘤弥漫浸润性生长，肿瘤细胞形态较一致，胞核圆形，可见神经毡背景和“树枝”状薄壁毛细血管。应注意与垂体腺瘤、少突胶质细胞瘤和透明细胞型室管膜瘤等相鉴别。

关键词: 神经细胞瘤, 蝶鞍, 病理学, 免疫组织化学

Abstract:

Objective  To explore the clinicopathological features of extraventricular neurocytoma located in the sellar/suprasellar region.  Methods  The clinical manifestations, neuroimaging, histopathological, immunohistochemical and molecular genetic features were retrospectively analyzed in one case of sellar/suprasellar extraventricular neurocytoma, and the related literatures were reviewed.  Results  A 27-year-old female presented with intermittent headache, accompanied by blurred vision for 5 months. Head MRI demonstrated a mass with a well-defined margin measuring 3.80 cm × 2.50 cm × 3.40 cm located in the sellar/suprasellar region. The tumor showed isointense to hyperintense signals on T₁WI and hyper-hypointense mixed signals on T₂WI, and slightly hyperintense signal on diffusion-weighted imaging (DWI). The pituitary was not shown. A transsphenoidal sellar tumor resection, cerebrospinal fluid (CSF) rhinorrhea repairing and optic decompression were performed. The mass was lightly yellow and tough with abundant blood supply and filled with old hemorrhage. The pituitary tissue was pushed to the left rear. Microscopy examination showed a diffuse invasive growth pattern with neuropil background in some area. The tumor cells were uniform on size and shape with round to oval, exquisite and hyperchromatic nuclei. No mitosis was found. Immunohistochemical staining showed the tumor cells were positive for neuronal nuclei (NeuN) and thyroid transcription factor-1 (TTF-1) in nuclei, calretinin (CR) in nuclei and cytoplasm, synaptophysin (Syn), chromogranin A (CgA), E-cadherin, matrix metalloproteinase-9 (MMP-9) in cytoplasm, and focally positive for S-100 protein (S-100) in nuclei, and neurofilament protein (NF), cytokeratin 8 (CK8) and vimentin (Vim) in cytoplasm. The Ki-67 labeling index was about 3%. The tumor tissue was negative for reticular fiber staining. Molecular genetic analysis showed that isocitrate dehydrogenasel (IDH) gene was not mutated, and 1p/19q was intact in tumor cells. The final pathological diagnosis was extraventricular neurocytoma, WHO grade Ⅱ.  Conclusions  Extraventricular neurocytoma located in the sellar/suprasellar region is very rare. The histological features are similar to central neurocytoma in ventricle. Tumor cells were in diffusely invasive growth and were uniform in size and shape, with round nuclei. Fibrillary areas mimicking neurophil and branching thin-walled capillaries can be seen. The differential diagnosis includes pituitary adenoma, oligodendroglioma, clear cell ependymoma, and so on.

Key words: Neurocytoma, Sellar turcica, Pathology, Immunohistochemistry