Medical Imaging Analysis Report

I. Radiological Findings

The patient is a 52-year-old female complaining of left heel pain for 5 months, with no clear history of trauma or weight loss. Based on the X-ray and CT findings:

• A relatively obvious focal lesion of low density or lucency is seen in the left calcaneus (in the area of the calcaneal “neutral angle” or “critical angle”), with well-defined margins.
• On X-ray, the lesion appears as a radiolucent area with a mild sclerotic rim around it. The internal structure is homogeneous, and there is no obvious sign of fracture.
• On CT scan, the density of the lucent area is similar to fat (approximately -40 to -110 HU), suggesting fatty components within the lesion.
• No evident soft tissue swelling or invasive changes were found, and there is no significant cortical bone destruction.

II. Possible Diagnoses

Based on the imaging findings and the clinical condition of the patient, the following differential diagnoses are considered:

1. Intraosseous Lipoma (Calcaneal Lipoma)
   Rationale: Lucent lesion, matching fat density, and well-defined margins are typical features of an intraosseous lipoma of the calcaneus.
2. Simple Bone Cyst
   Rationale: Can also appear as a lucent lesion, but usually does not exhibit fat density on CT and often occurs in the metaphysis of long bones.
3. Aneurysmal Bone Cyst (ABC)
   Rationale: May also present as a cystic radiolucent lesion on X-ray, often with septations and blood flow characteristics. On CT or MRI, there is typically enhanced septation, which does not match the fatty characteristics seen in this case.
4. Giant Cell Tumor (GCT)
   Rationale: Commonly included in the differential diagnosis for adult patients. However, GCTs often exhibit an expansile, destructive pattern, frequently extend to the articular surface, and show mixed density on CT. These findings differ from this case.

III. Final Diagnosis

Considering the patient's age, clinical symptoms (persistent heel pain for 5 months), the typical imaging feature of fat density, and absence of malignant signs, the most probable diagnosis is:

Intraosseous Lipoma of the Calcaneus (Milgram Stage I).

If clinical symptoms worsen later, further evaluation such as MRI or, if necessary, biopsy should be performed to exclude the rare possibility of malignancy.

IV. Treatment Plan and Rehabilitation

1. Treatment Strategy
• Symptomatic Treatment: If symptoms are mild, conservative management can be considered, including reducing excessive weight-bearing, using heel pads or external supports to relieve pain and stress.
• Surgical Intervention: For persistent symptoms, notable enlargement, or if there is a risk of fracture, curettage of the lesion and bone grafting may be considered to stabilize the bone structure and alleviate symptoms.
2. Rehabilitation and Exercise Prescription (FITT-VP Principle)

During symptomatic relief or post-surgery rehabilitation, an individualized and stepwise exercise plan should be followed:

• Type:
  Focus on low-impact exercises, such as swimming, seated cycling, resistance band training, and light walking, to reduce stress on the calcaneus.
• Frequency:
  Begin with 2–3 sessions per week. As pain improves and bone healing progresses, gradually increase to 3–4 sessions per week.
• Intensity:
  Start at a level that does not cause obvious heel pain, initially around below 40% Heart Rate Reserve (HRR). Increase slowly depending on individual tolerance.
• Time:
  Each session about 20–30 minutes; can be extended to around 40 minutes after adaptation. If significant discomfort occurs, rest and adjust accordingly.
• Progression:
  Once the patient can complete the original intensity without pain, gradually increase intensity or duration. Adjust every 2–4 weeks based on individual response.
• Volume:
  Initially aim for a total weekly exercise duration of 50–90 minutes. Increase according to recovery status, ensuring sudden increases are avoided to prevent stress-related injuries.

Safety Considerations:
For middle-aged or first-time rehabilitation participants, regular follow-up on bone healing is advisable. Use appropriate shoe inserts or supports during training to avoid excessive load that could lead to stress fractures.

Disclaimer:

This report is a reference analysis based on clinical and imaging data provided by the patient. It cannot replace an in-person consultation or professional medical advice. Please follow the recommendations of a specialist physician or seek further investigations as necessary.