Objective: To investigate the clinicopathological features, immunophenotype, molecular characteristics and differential diagnosis of primary skull base chondrosarcoma. Methods: Nine cases of primary skull base chondrosarcoma were collected at the First Affiliated Hospital of Fujian Medical University, from January 2006 to June 2019, reviewed for the clinical and radiologic data and morphologic features, immunophenotype and molecular characteristics. Results: Among all the 9 cases, six were male, three were frmale, with average age 47 years, and median age 47 years; five cases were WHO gradeⅠ, and four were WHO grade Ⅱ. Microscopically, the tumor showed lobulated growth pattern with low-medium cellularity within a chondroid or mucoid background. The tumor cells showed mild-moderate atypia, with binucleated forms, and mitosis was rare or occasional. Immunohistochemistry (IHC) showed tumor cells were positive for S-100 protein, vimentin, SOX-9 and D2-40, and negative for Brachyury, CK, EMA and CK8/18; the Ki-67 index was low (1% to 5%). Molecular analysis showed IDH1 R132C mutation in four cases. Conclusions: Skull base chondrosarcoma is a rare cartilaginous malignant tumor with a good prognosis. Its characteristic morphologies, combined with IHC and molecular detection are helpful for the differential diagnosis.
目的： 探讨原发性颅底软骨肉瘤的临床病理特点、免疫表型、分子特征及鉴别诊断。 方法： 收集福建医科大学附属第一医院2006年1月至2019年6月9例原发性颅底软骨肉瘤的临床资料、影像学表现、大体及镜下形态、免疫表型及分子特征。 结果： 9例患者中6例男性，3例女性，平均年龄47岁，中位年龄47岁。5例为WHOⅠ级肿瘤，4例为WHOⅡ级。镜下于软骨样或黏液样基质的背景中，见低-中等密度的肿瘤细胞呈结节状生长，细胞轻-中度异型，可见双核细胞，核分裂象罕见或偶见。免疫组织化学示肿瘤细胞S-100蛋白、波形蛋白、SOX9、D2-40阳性，Brachyury、细胞角蛋白（CK）、上皮细胞膜抗原（EMA）、CK8/18阴性，Ki-67阳性指数低（1%~5%）。分子检测4例呈IDH1 R132C位点突变。术后4例辅助放疗，随访1~59个月，8例存活。 结论： 颅底软骨肉瘤是罕见的软骨来源的恶性肿瘤，预后好，其特征性的组织学表现结合免疫组织化学和分子检测有助于鉴别诊断。.
Keywords: Chondrosarcoma; Diagnosis, differential; IDH 1/2; Immunohistochemistry; Molecular diagnostic techniques; Skull base.