The most common clinical presentation is that of a localized, painful mass. The radiologic picture of fibrosarcoma is that of an osteolytic lesion. Periosteal reaction is seen with cortical destruction. Extension into the soft tissue is common. MRI helps define intraosseus spread and soft tissue extension.
Bone scan demonstrates increased uptake.
The differential diagnosis includes leiomyosarcoma, metastatic carcinoma, melanoma, malignant fibrous histiocytoma and multiple myeloma. On gross examination the tumor is tan to grayish white with a rubbery consistency. Larger tumors may have hemorrhagic and necrotic foci. As with plain x-ray, the microscopic appearance of fibrosarcoma varies with the level of differentiation. A well differentiated, low grade tumor has homogeneous spindle shaped fibroblasts with ovoid nuclei.