A 45-year-old male patient was referred for further characterisation of a right hip bony lesion, detected 5 months earlier.
A 45-year-old male patient was referred for further characterisation of a right hip bony lesion.
The initial radiographs document a geographic lesion, with a well-defined and thick sclerotic margin, and amorphous mineralised matrix, localized in the intertrochanteric region of the right femur (Figure 1).
The positron emission tomography - computed tomography (PET-CT) with fluorodeoxyglucose (FDG) demonstrates moderate uptake of radiopharmaceutical by the lesion (Figure 2).
Magnetic resonance (MR) demonstrates the mixed nature of the lesion’s core, composed of hypointense areas on all sequences as well as other areas with low signal on T1 and high signal on T2 and STIR, indicating its sclerotic and myxomatous components respectively (Figure 3). The thick margin exhibits low signal on all sequences confirming its sclerotic nature. The lesion's high signal on STIR demonstrates the absence of macroscopic fat.
The radiographs performed 5 months later document the unchanged appearance of the intertrochanteric lesion (Figure 4).
The differential diagnosis of a geographic lesion predominantly sclerotic, with well-defined and thick margins includes fibrous dysplasia, liposclerosing myxofibrous tumour of bone (LSMT), and intraosseous lipoma.
The absence of macroscopic fat disfavours intraosseous lipoma’s diagnosis. The distinction between LSMT and fibrous dysplasia may be hazardous. Fibrous dysplasia’s signal on fluid-sensitive sequences is variable but fibrous dysplasia characteristic pattern of intermediate or decreased signal has not been described in LSMT's patients.
Considering the age, the imaging features, and the intertrochanteric location observed in the case presented, LSMT was the diagnosis established and pursue of imaging follow-up was advised.
Liposclerosing myxofibrous tumour of bone is a benign fibro-osseous lesion characterised by a suggestive radiologic appearance and a complex mixture of histological elements. It has been referred to as “polymorphic fibrocystic disease of bone” and “polymorphic fibro-osseous lesion of bone”; however, the descriptive term Liposclerosing myxofibrous tumour of bone (LSMFT) is preferred.
LSMFT’s origin remains unclear presumed to be a combination of alterations in a partially involuted lipogenic bone lesion and superimposed proliferative changes which include myxolipomatous, myxomatous, myxofibrous, fibrous, and fibro-osseous features. Genetic analysis suggests that LSMFT may represent a variant of fibrous dysplasia. Indeed, although LSMFT shares histological similarities with involuting lipoma and fibrous dysplasia, its histological pattern is complex and goes beyond the current description of these entities.
LSMFT has a wide age of presentation, being more common in the 4th-5th decades. While it is often incidentally discovered, LSMFT may be presented by local pain and rarely pathologic fracture. Asymptomatic lesions do not require other care than surveillance. Symptomatic LSMFT’s lesions treatment includes curettage, bone grafting, fixation, and possibly joint arthroplasty.
LSMFT’s radiological appearance is often quite characteristic. LSMFT has a striking predilection for the femur, particularly for the intertrochanteric region, this being the location of more than 85% of LSMFT’s lesions.
Radiographs typically show a geographic lytic or ground glass lesion with a well-defined, often extensively sclerotic margin, indicating its indolent nature. The contour of the involved bone is usually normal or with mild expansive remodelling. Amorphous mineralisation is present in most lesions.
Bone scintigraphy can exhibit mild to marked focal radionuclide accumulation within the lesion, the most common pattern being moderate accumulation, in a degree usually less intense than that observed in fibrous dysplasia.
Despite its name, lipomatous tissue is not identified on CT and MR imaging, probably due to the small amount of fat and its mixture with the more prominent myxofibrous and/or fibro-osseous tissue.
MR can display the well-defined low signal margin of variable thickness that corresponds to sclerosis also documented radiographically. On T1-weigthed images (WI), the lesions are relatively homogeneous and most commonly are isointense to skeletal muscle. On T2-WI, the lesions are mildly to moderately heterogeneous, with signal intensity equal to or greater than fat. The high signal on T2-WI is in likely relation with the myxoid tissue component. The characteristic areas of mineralised matrix exhibit decreased signal on all sequences.
LSMFT’s differential diagnosis includes the fibro-osseous lesions with which it shares tissue components, particularly fibrous dysplasia, intraosseous lipoma, and osseous myxoma.
An important feature of LSMFT is its small malignant potential. The propensity to undergo malignant transformation probably relates with LSMFT’s extensive involutional and ischemic changes, with the associated sarcoma arising from ischemic ossification areas or from progressive in situ atypism of the altered lipomatous elements.
The case presented discusses the differential diagnosis making of intertrochanteric femoral lesions on the adult. LSMFT is a bone lesion distinctive for its radiologic appearance and typical skeletal distribution which are exemplified and demonstrated in the case presented.
Lyposclerosing myxoid tumor of bone
Based on the provided X-ray and MRI images, the lesion is located in the intertrochanteric region of the proximal right femur. X-ray findings include:
MRI shows:
These imaging findings match the location of the lesion discovered clinically five months ago, overall suggesting a relatively indolent, benign fibro-osseous lesion.
Based on the patient’s age (45-year-old male), lesion location (proximal femoral intertrochanteric region), imaging characteristics, and the generally benign appearance, the differential diagnoses include:
Considering the patient’s age, clinical presentation (whether pain or an incidental finding), the current imaging features, and a review of the differential diagnoses, the most likely diagnosis is:
Liposclerosing Myxofibrous Tumor (LSMFT).
If definitive confirmation is needed, further imaging follow-up or biopsy can be performed to verify the lesion’s nature based on growth characteristics and patient symptoms.
Treatment Strategy:
Rehabilitation and Exercise Prescription Advice:
As LSMFT is related to bone strength and soft tissue integrity, rehabilitation should be conducted cautiously and progressively, following the FITT-VP principles:
In view of the vulnerability of the affected area (the right hip joint and proximal femur) or potential postoperative condition (e.g., after curettage and bone grafting), precautions should be taken to prevent falls and excessive twisting movements. For individuals with weaker bone quality or reduced hip joint function, protective supports or braces are recommended during ambulation.
This report is a reference analysis based on current imaging and clinical data and should not replace in-person medical evaluation or the advice of professional healthcare providers. A definitive treatment plan must be determined by qualified orthopedic or related specialists, taking into account the patient’s specific circumstances, intraoperative findings, and pathological results.
Lyposclerosing myxoid tumor of bone
