Fibrosarcoma

19-year-old female with slowly growing tender mass over the medial aspect of the lower right leg. The images demonstrate an infiltrative T1 hypointense, STIR heterogeneously hyperintense mass centered within the medullary cavity of the distal right tibial diaphysis. There are components of the lesion which extend into the surrounding musculature with marked peripheral edema. There is florid periosteal reaction and cortical discontinuity along the medial distal aspect of the right tibia. There is avid but heterogeneous enhancement. This is the case of a high grade fibrosarcoma. Fibrosarcomas are rare malignant bone tumors which can occur in primary and secondary forms. Secondary forms occur in the setting of prior radiation treatment, dedifferentiation from other pathology such as Pagets disease, bone infarction, or chronic osteomyelitis. Patients are typically 30 to 60 years old at time of presentation with a slight male prominence.