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

XIONG Zhen-fang; HU Xiu-hua; XIONG Xin; XIONG Qiu-ying; XIONG Lei; MEI Jin-hong

doi:10.3969/j.issn.1007-8096.2017.03.003

Abstract：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,CgA,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.