摘要： 目的 化生型脑膜瘤临床少见，对其临床表现和组织病理学特征进行探讨，并复习相关文献，避免误诊。方法与结果 女性患者，17 岁，彝族。临床表现为突发性头痛、呕吐、发热伴四肢抽搐。头部CT 显示右侧额顶叶不规则低密度影，边界欠清晰，其内含类钙化高密度影，大小约2 cm × 1.80 cm ×1.70 cm；MRI 可见右侧额顶叶大小约2.40 cm × 2.10 cm × 2 cm 的肿瘤影，周围脑组织大片状水肿。术中于右侧额顶叶脑实质内见一占位性病变，一侧紧邻软脑膜，未侵及硬脑膜和颅骨，形状不规则，边界较清晰，表面血供丰富，呈黄色、质地较硬，大小约3 cm × 2.50 cm × 2 cm。光学显微镜观察肿瘤组织广泛骨化和钙化，肿瘤细胞呈片状和小巢状分布在网状排列的小梁状骨组织间；肿瘤细胞表达上皮膜抗原、孕激素受体、波形蛋白和Bcl-2，Ki-67 抗原标记指数约为6%。结论 化生型脑膜瘤的化生成分多种多样，其影像学也存在多样性，通过组织形态学和免疫组织化学可明确诊断，并与其化生成分相似的肿瘤进行鉴别，以免误诊。

关键词: 脑膜瘤, 化生, 免疫组织化学, 病理学

Abstract: Objective  Metaplastic meningioma is rare lesion which is very difficult to diagnose clinically, and is easy to be misdiagnosed. This article aims to reveal the clinical manifestations and histopathological features of this disease.  Methods  One case of ossification metaplastic meningioma was reported and the relevant literatures were reviewed.  Results  A 17-year-old female patient showed paroxysmal stiffness accompanied by convulsion of extremities, headache, vomiting and fever. Cranial CT scan demonstrated an irregular low-density signal in the right frontal and parietal lobes. The lesion did not have a clear boundary, and there was a calcificated high-density signal inside it. The size of the lesion was about 2 cm × 1.80 cm × 1.70 cm. Cranial MRI scan showed a tumor with size of 2.40 cm × 2.10 cm × 2 cm, located in the right frontal and parietal lobes, and there was large edema around the lesion. A resection was performed, and a lesion was found in the right frontal and parietal parenchyma, whose one side was close to the cerebral pia mater and did not invade into the dura and the skull. The tumor was yellow, in irregular shape, and had clear boundary, with hard texture and rich blood supply. Its size was about 3 cm × 2.50 cm × 2 cm. There was extensive ossification and calcification within the tumor under microscope. Tumor cells were flaky and like small nests, which were distributed in the mesh?like arranged trabecular bone. The immunohistochemical staining showed that epithelial membrane antigen (EMA), progesterone receptor (PR), vimentin (Vim) and Bcl-2 were positive for tumor cells with Ki-67 labeling index being about 6%.  Conclusions  Metaplastic meningioma has various metaplastic components and its imaging features are also various. However, it could be diagnosed and identified from other similar tumors by histopathological observation and immunohistochemical staining.

Key words: Meningioma, Metaplasia, Immunohistochemistry, Pathology