Presentation
Referred for incidental right upper femur osseous lesion with a vague history of long duration hip pain.
Patient Data
Right upper femur expansile geographic lucent multilocular lesion centered in the intertrochanteric region of the proximal femur with sclerotic margin
Right upper femur namely neck and upper shaft expansile central medullary lesion. The lesion has well-defined margins with evidence of cortical breaching along the medial aspect of the femoral neck. The bony lesion measure about 3.2 x 3.8 x 5.8 cm along its maximal axial and cranio-caudal dimensions. The lesion elicits low signal on T1 Wis, a high signal on T2 and STIR WIs with an area of intermediate T1 and T2 WI signal along its superior portion measuring 2.8 cm showing heterogeneous enhancement along its superior portion. The lesion is seen marginated by the sclerotic rim with internal fine septations within. No related soft tissue components are seen.No MR evidence of involvement of the adjacent joint. No skip lesions could be detected with normal bone marrow signal of the other bony structures.
Case Discussion
Right proximal femoral expansile osseous lesion. The diagnostic possibilities include liposclerosing myxo-fibrous tumor, aneurysmal bone cyst, intra-osseous lipoma and less likely fibrous dysplasia.
Fibrous dysplasia may have less sclerosis, intraosseous lipoma has macroscopic fat on CT or MRI and aneurysmal bone cyst (ABC) is usually more expansive and may show fluid/fluid levels.
In a liposclerosing myxofibrous tumor. The lipomatous component is usually too small and mixed with other more prominent myxofibrous or fibro-osseous tissue.
A biopsy was done with the microscopic picture showing sclerotic bone trabeculae with intervening fibrotic stroma and wide areas of hemorrhage, dense fibrosis, and focal fat necrosis. No atypia of malignancy. Pathological findings matched the radiological diagnosis of liposclerosing myxo-fibrous tumoor.
‘LSMFT’ was the acronym for an old American tobacco commercial ‘Lucky Strike Means Fine Tobacco’, whose name is equally applicable to the liposclerosing myxo-fibrous tumor. The large lesion of the femoral neck with a sclerotic margin, no capsule, no communicating channel, containing ‘myxoid type tissue with adipose elements and some atypical features’. The multilobular character, transversely intact trabeculae and areas of micronodular bone formation are features of LSMFT 1.
LSMFT is a benign, indolent fibro‐osseous lesion with sclerotic margins that has a striking predilection for the femoral neck (90%). LSMFT complications are uncommon with reported pathological fracture about 10% and rarely malignant transformation into osteosarcoma 2.
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