Correlation Between The Malignant Grade Of Osteosarcoma And The Existence Of Tumor Bone As Well As Its CT Value

Objective To investigate the relationship between the malignant grade of osteosarcoma and the existence of tumor bone as well as its CT value.Methods 50 cases of pathologically proved osteosarcoma were reviewed and divided into two groups of high and low malignant.In the high-grade group of osteosarcoma,there were 16 cases of osteoblastic osteosarcoma,3 cases of telangiectatic osteosarcoma,3cases of chondroblastoma-like osteosarcoma,5 cases of fibroblastic osteosarcoma,2cases of malignant fibrous histocytoma-like osteosarcoma,1 case of osteosarcoma rich of giant cell and 1 case of undifferentiated osteosarcoma.In the low-grade group of osteosarcoma,there were 9 cases of osteoblastoma-like osteosarcoma,1 case of periosteal osteosarcoma,1 case of low grade central osteosarcoma,2 cases of fibroblastic osteosarcoma,1 case of sclerosing type osteosarcoma and 5 cases of chondroblastic osteosarcoma.The occurrence rate of tumor bone,the mean value and Standard deviation of tumor bone were analyzed in the high and low malignant groups respectively.The relationships between the malignant grade of osteosarcoma and the existence of tumor bone as well as its CT value were analyzed with Chi-square test and t-test.Results In the 31 cases of high-grade group of osteosarcoma,18 cases were found tumor bone in soft tissue,which included 10 cases of osteoblastic osteosarcoma,1 case of telangiectatic osteosarcoma,2 cases of chondroblastoma-like osteosarcoma,3 cases of fibroblastic osteosarcoma,1 case of malignant fibrous histocytoma-like osteosarcoma and1 case of osteosarcoma rich of giant cell.In the 19 cases of low-grade group of osteosarcoma,13 cases were found tumor bone in soft tissue,which included 6 cases of osteoblastoma-like osteosarcoma,1 case of periosteal osteosarcoma,1 case of low grade central osteosarcoma,1 case of fibroblastic osteosarcoma,1 case of sclerosing type osteosarcoma and 3 cases of chondroblastic osteosarcoma.58.1%(18/31)of high-grade of osteosarcoma and 68.4%(13/19)of low-grade of osteosarcoma were found tumor bone in soft tissue.The Chi-square test indicated that there was no significant difference between the group of low and high malignancy(χ~2=0.02,P>0.05).13 cases of high-grade and 18 cases of low-grade malignant osteosarcomas were found tumor bone in soft tissue.The average CT value of tumor bone in the high malignant group and low malignant group were 412.65±132.69Hu and 610.66±199.62Hu respectively.The t-test indicated that there was significant difference between the group of low and high malignant(t=3.32,P<0.05).The average CT value of tumor bone in the high malignant group was lower than that in the low malignant group.Conclusion There is no relevance between the existence of tumor bone and the malignant grade of osteosarcoma.But there are associations between the malignant grade of osteosarcoma and CT value of tumor bone.Lower CT value of tumor bone suggests higher malignant degree of osteosarcoma,and higher CT value of tumor bone suggests lower malignant degree of osteosarcoma.