Liposclerosing myxofibrous tumor
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Liposclerosing myxofibrous tumor (LSMFT) of bone, a benign fibro-osseous lesion, is characterized by a complex mixture of histologic elements. These include lipoma, fibroxanthoma, myxoma, myxofibroma, fibrous dysplasia –like features, cyst formation, fat necrosis, ischemic ossification, and, rarely, cartilage. LSMFT has a striking predilection for the femur (approximately 85% of the lesions). Approximately 91% of the femoral lesions are in the intertrochanteric region. The prevalence of malignant transformation in LSMFT has been reported to be 10%–16%. The increased propensity of LSMFT for malignant transformation is likely to be secondary to its extensive involutional and ischemic change, with the associated sarcoma arising from areas of ischemic ossification within the lesion or from progressive in situ atypism of the altered lipomatous elements.
Diagnosis
The imaging findings are
- Radiographs typically showed a geographic lesion with a well-defined, often extensively sclerotic margin; such findings indicate an indolent pattern of growth.
- Despite its name, lipomatous tissue was not identified on CT and MR imaging studies.
- Myxoid tissue causes decreased attenuation seen in portions of the lesions on the CT scans and causes the high signal intensity seen on the T2-weighted MR images.
- LSMFT can be readily distinguished from intraosseous lipoma on CT scans or MR images by the identification of fat within a lipoma.
CT images of a liposclerosing myxofibrous tumor in the right femur
