Imaging Findings

The patient is a 43-year-old female presenting with right trochanteric region pain. She has a history of untreated hyperlipidemia and denies any recent trauma or falls. Comparing the previously provided X-ray, CT, and MRI images, the findings are as follows:

• Bone Changes: Bilateral proximal femurs (mainly in the metaphyseal region) show relatively well-defined lytic-like lesions, with partial sclerotic margins. The internal trabecular structure is lost or disorganized.
• CT Findings: The lesions exhibit varying degrees of increased density. The “soft tissue” density suggests a high proportion of cholesterol and foam cells. Some lesions show a mild “ground-glass” density.
• MRI Signals: On T1-weighted images, the lesions mostly present relatively low or mixed signal intensity. On T2-weighted images, the signal tends to be higher, with a low-signal band suggesting possible reactive sclerosis. On fat suppression sequences, the lesion signals markedly decrease, consistent with tissue containing lipids or cholesterol.
• Surrounding Soft Tissue: No significant soft tissue mass or obvious soft tissue edema is observed.

Potential Diagnoses

Based on the imaging characteristics and the patient’s medical history, the following conditions should be considered:

1. Bone Xanthoma (Xanthoma of the Bone, XOB): Possibly related to hyperlipidemia. Pathologically, large amounts of cholesterol clefts and foam cells may be found, often with CD68 positivity on immunohistochemistry, which aligns with the history of hyperlipidemia and the imaging features.
2. Fibrous Dysplasia: Can present with a “ground-glass” appearance on imaging, but it is more common in younger populations and often shows “soap bubble” or “blow-out” expansion. The MRI signal patterns also differ from this case.
3. Non-ossifying Fibroma (NOF): Frequently seen in children and adolescents; rare in adults. Imaging usually shows a well-defined lytic lesion, but this patient’s age and clinical background do not fully match with NOF.
4. Intraosseous Lipoma: On CT, negative Hounsfield values or fatty density are commonly noted; on MRI, a typical fatty signal is seen. The CT density and MRI signals in this case do not match an intraosseous lipoma.

Final Diagnosis

Considering the patient’s age, clinical symptoms (right trochanteric region pain), history of hyperlipidemia, and the imaging findings, along with the typical pathological and immunohistochemical results (cholesterol clefts, CD68-positive staining), the most likely diagnosis is: Bone Xanthoma (Xanthoma of the Bone).

If uncertainty remains, further histopathological or immunohistochemical examinations can be performed for confirmation. However, based on the available data, bone xanthoma is the most consistent diagnosis.

Treatment Plan and Rehabilitation Program

Treatment Strategy:

• Metabolic Management: Due to the patient’s history of hyperlipidemia, prompt lipid control is recommended, including dietary management, exercise intervention, and potentially lipid-lowering medications (e.g., statins).
• Surgical Intervention: For patients with significant symptoms, larger lesions, or compromised mechanical stability, curettage of the lesion or lesion resection with bone grafting can be considered, especially if there is marked pain or the risk of pathological fracture.
• Follow-up Observation: If the lesion is relatively limited and symptoms are mild, conservative treatment with regular imaging follow-up and lipid control can be pursued.

Rehabilitation and Exercise Prescription:

• General Principles: A gradual, individualized approach is recommended (step-wise increase in intensity, frequency, and duration). All exercises should be undertaken under the guidance of a physician or physical therapist to ensure safe weight-bearing.
• Initial Phase (Preoperative, Early Postoperative, or Conservative Period):
  • Focus on non–weight-bearing or partial weight-bearing exercises, such as seated quadriceps isometric contractions and gentle range-of-motion exercises for the lower limbs.
  • Perform 2–3 sessions daily, each lasting 10–15 minutes, with low intensity. The goal is to maintain joint mobility and muscle endurance.
• Intermediate Phase (After Pain Relief):
  • Gradually increase weight-bearing exercises, such as assisted walking with a walker or crutches, and small-range closed-chain exercises (e.g., seated partial squats).
  • Exercise frequency can be increased to 3–4 times per week, 20–30 minutes per session. Introduce slight resistance, for example with light resistance bands.
• Advanced Reinforcement Phase:
  • When the lesion is stable and bone strength is adequate, progress to single-leg weight-bearing exercises, seated or standing squats, and incorporate moderate plyometrics or other functional drills.
  • Maintain a frequency of 3–5 sessions per week, gradually increasing intensity to a moderate level, and extend session duration to 30–45 minutes. Include aerobic activities such as elliptical machines or cycling, ensuring safety at all times.
  • Monitor improvement closely and adjust training regimens if pain or fatigue worsens.
• Precautions: If hip pain or discomfort significantly worsens, imaging reevaluation should be performed and increased load exercises should be paused. Patients with limited cardiopulmonary reserve should undergo an appropriate cardiac and respiratory assessment before commencing exercise.

Overall Goal: To improve lipid control, alleviate pain, and progressively enhance hip and lower-limb function and strength, thereby reducing the risk of pathological fractures.

Disclaimer: The above report is for reference only and cannot replace an in-person consultation or individualized assessment by a qualified physician. If you have any questions or if symptoms worsen, please seek medical attention promptly.