Objective: To study the clinicopathologic features of dedifferentiated chordoma. Methods: Four cases of dedifferentiated chordoma of sacrococcygeal region were collected at Beijing Jishuitan Hospital, from 2009 to 2014. HE and immunohistochemistry (EnVision method) were used to observe the clinical, radiological and histological features of dedifferentiated chordoma and to make the diagnosis and differential diagnosis. The literature was reviewed. Results: Four cases of dedifferentiated chordoma were all located in the sacrococcygeal region. The mean age at diagnosis was 57 years (range 49-64 years). There were 1 female and 3 males. Histologically, there were two components of conventional chordoma and dedifferentiated sarcoma with or without transitional area between them. The histology of dedifferentiated components includes undifferentiated sarcoma and fibrosarcoma. Immunohistochemical study showed that cytokeratin, epithelial membrane antigen, S-100, Brachyury were positive in the portion of chordoma while p53 were positive in the portion of undifferentiated sarcoma. INI1 and vimentin were both positive. Conclusions: The dedifferentiated chordoma is very rare. The diagnosis should combine the histological characters and immunohistochemical results and should be differentiated from the sarcomatoid chordoma, poorly differentiated chordoma and other high grade sarcoma. p53 may play a role in the malignant transformation mechanism of chordoma.
目的： 探讨骶尾部去分化脊索瘤的临床病理特征、诊断及鉴别诊断。 方法： 收集北京积水潭医院2009—2014年骨科手术标本中去分化脊索瘤4例，通过HE、免疫组织化学染色(EnVision法)对4例骶尾部去分化脊索瘤的临床影像学及病理学特征进行分析，并对其进行鉴别诊断。 结果： 4例去分化脊索瘤，年龄49～64岁，平均57岁，女性1例，男性3例。均发生于骶尾部。组织学上均存在经典的脊索瘤结构，3例去分化成分为未分化肉瘤，且在经典脊索瘤与肉瘤成分间分界较清，其中1例脊索瘤成分呈结节状分布于肉瘤成分中。1例去分化成分为纤维肉瘤，脊索瘤细胞散在分布于纤维肉瘤间。免疫组织化学经典的脊索瘤结构细胞角蛋白、上皮细胞膜抗原、S－100蛋白、Brachyury阳性，波形蛋白、INI1在两种成分中均阳性。p53的表达在未分化肉瘤中明显升高，但在纤维肉瘤中仅个别细胞表达。 结论： 去分化脊索瘤较少见，其形态可结合免疫组织化学与肉瘤样脊索瘤、原发性未分化肉瘤及儿童的分化较差的脊索瘤等鉴别。p53可能在脊索瘤的恶性转化机制中起一定作用。.
Keywords: Chordoma; Diagnosis, differential; Immunophenotyping; Sacrococcygeal region.