少见部位间叶性软骨肉瘤5例临床病理分析

Mesenchymal chondrosarcoma in rare locations: a clinicopathologic analysis of five cases

目的分析间叶性软骨肉瘤(MC)的临床病理学和免疫组化特点,探讨其诊断、鉴别诊断依据和预后。方法采用HE及免疫组化En Vision两步法对5例MC进行观察,并随访。结果 5例中,女性3例,男性2例。1例原发于骨(左上颌骨),3例原发于软组织,部位分别位于盆腔后腹膜、大阴唇和右大腿;1例原发于脑组织(左颅底近舌下神经管区)。临床表现主要为疼痛、肿胀和局部肿块。主要影像学特点为溶骨性破坏或软组织肿块伴肿瘤内钙化和肿瘤边缘硬化。镜下肿瘤由未分化的小圆细胞和肿瘤性透明软骨小岛组成。软骨区的分化程度不等,可以是分化良好的软骨岛,也可以是不成熟的低级别软骨肉瘤。免疫组化:未分化小细胞CD99、Syn、CgA、NSE、vimentin和bcl-2(+);软骨区S-100(+);40%~70%的肿瘤细胞核Ki-67、p53(+)。结论 MC是一种罕见的高度恶性肿瘤,其组织学特点是小细胞原始间叶组织向幼稚软骨组织分化,其诊断要点是在未分化的小细胞区找到分化较成熟的软骨组织。活检小标本容易误诊,须结合组织学特征、影像学表现及免疫组化与其他肿瘤相鉴别。

Objective To investigate the clinicopathological and immunohistochemical characteristics of mesenchymal chondrosarcoma（ MC） and to discuss the diagnosis,differential diagnosis and prognosis. Methods 5 cases of mesenchymal chondrosarcoma were analyzed by HE,immunohistochemical staining and followed-up. Results With five patients,3 cases were female,2 cases were male. 1 case of primary tumor was located in bone（ upper jaw）; 3 cases of primary tumor were located in soft tissues,which were in pelvic retroperitoneum,labia majora,right thigh; 1 case was located in the basis cranii（ the left hypoglossal canal area）. The main imaging characteristics were rock-salt bony destruction or soft tissue mass with calcification and tumor edge hardening. The histological characteristic features showed undifferentiated small cells together with islands of chondrosarcoma. The tumor cells were positive for CD99,Syn,Cg A,NSE,Vimentin,and bcl-2. The cells in chondroid matrix were positive for S-100. From 40% to 70% of the tumor cell nucleus showed positive expression of Ki-67 and P53. Conclusion MC is a rare,highly malignant cartilaginous tumor.It has the characteristics of primary mesenchyme which differentiates to congenital cartilage. The pathological characteristics of bimophic pattern and roentgenographical appearance of tumor are useful for diagnosis. It is easy to misdiagnosed in biopsy specimens. Combined with histological characteristics,imaging findings and immunohistochemical phenotype are helpful for differential diagnosis.