Benign Fibrous Tumors and Tumorous Lesions of the Bone

-Abstract=We report here 6 cases with classical forms of nonossifying fibroma (NOF) and 1 case of fibrous cortical defect (FCD) which occurred in the metaphysis of the long bones of children along with 2 cases of fibrous histiocytoma (FH) which occurred in the veretebra and femur neck of adults. Their clinical data, radiographs, histopathology, and ultrasturctural features are described. Through these series, we concluded that microscopic and ultrastructural findings are not basically different among NOF, FCD, and FH. NOF is different from FCD in the extent of the disease, the latter involving only the cortex, which is best evaluated by radiological examination. The FH cases were located in sites other than the metaphysis of the long bones and were older than FCD or NOF. Our data concurred with the previous notion that the FCD and NOF(MFD) are evolutionary forms of the same process. It is believed that certain lesions that we called fibrous histiocytoma of the bone do exist based on their microscopic similiarities to fibrous histiocytoma of the soft tissue, although they can be put into NOF or FCD by the age and site of the involvement.