Medical Imaging Analysis Report

I. Imaging Findings

The patient is a 10-year-old boy who developed acute, spontaneous pain in the left hip region after physical activity. Based on the provided imaging data (including X-ray and MRI), a notable cystic lesion is observed in the left proximal femur (near the trochanteric region):

• On X-ray: There is a lucent area in the central region of the proximal femur with clear definition and relatively regular boundaries. The cortical bone appears thinned but does not show obvious invasion of the surrounding tissues. The lesion shows a single-chamber feature, and slight cortical expansion can be observed corresponding to the cystic area.
• On MRI: The lesion demonstrates low signal on T1-weighted images and high signal on T2-weighted images, consistent with a cystic characteristic. After contrast enhancement, a thin rim enhancement is observed, aligning with common enhancement patterns in cystic bone lesions.
• Clinical examination shows local tenderness and pain with joint movement, suggesting a possible pathologic fracture or impending fracture. If a “Fallen Fragment Sign” is present, it would further suggest an internal fracture fragment within the cystic lesion.

II. Potential Diagnoses

Based on the patient’s age, imaging findings, and clinical presentation, the following diagnoses or differential diagnoses are considered:

1. Solitary Bone Cyst (SBC): Commonly seen in children and adolescents, often located in the metaphysis of long bones. X-ray demonstrates a well-defined radiolucent area, MRI shows a cystic lesion, and post-contrast imaging often reveals a thin rim enhancement.
2. Aneurysmal Bone Cyst (ABC): Often presents as an eccentric destructive lesion. On MRI, multiple septations and typical fluid-fluid levels may be visible. This case does not show the characteristic fluid-fluid levels on imaging.
3. Fibrous Dysplasia: On X-ray, a “ground-glass” appearance is commonly observed. However, this case shows a well-defined lucent area with a distinct cystic characteristic, which does not match fibrous dysplasia.
4. Brodie’s Abscess: Typically accompanied by a sclerotic margin, significant pain, and prominent bone marrow edema, often associated with a chronic or subacute infection. There are no obvious signs of infection in this case.
5. Giant Cell Tumor (GCT): More frequently seen in adults (after epiphyseal closure) and usually located near joints. On MRI, GCTs often exhibit a heterogeneous signal. Given this patient’s young age and the lesion’s morphology, a benign cystic lesion is more likely.

III. Final Diagnosis

Considering the patient’s age, pain characteristics, and imaging findings (a single-chamber cystic radiolucent area, thin rim enhancement, located in the proximal femur near the trochanteric region), the most likely diagnosis is a Solitary Bone Cyst (SBC).

If subsequent imaging follow-up or pathological examination confirms these features, the diagnosis can be definitively established.

IV. Treatment Plan and Rehabilitation

(A) Treatment Strategy

• If the lesion is small and shows no significant clinical symptoms, conservative observation may be considered. Regular imaging follow-up is recommended since solitary bone cysts often tend to improve or significantly decrease in size after physeal closure.
• If the lesion is large with a clear risk of pathologic fracture, the following interventions may be considered:
  • Corticosteroid Injection: May facilitate closure or shrinkage of the cyst.
  • Curettage and Bone Grafting: Indicated for larger lesions or those with a pathologic fracture.
  • Internal Fixation: For lesions in the proximal femur that have fractures or a high risk of fracture, dynamic hip screw (DHS) or other fixation methods may be employed to maintain stability and promote healing.

(B) Rehabilitation / Exercise Prescription

A gradual rehabilitation program based on the FITT-VP principle is recommended, tailored to the type of surgery or conservative treatment:

1. Early Phase (Postoperative or early conservative treatment):
   • Frequency: Several sessions of light activity per day, such as bed-based or seated joint mobility exercises.
   • Intensity: Low-intensity; avoid excessive weight-bearing and overly large ranges of motion of the hip joint.
   • Time: 5–10 minutes per session, repeated multiple times per day.
   • Type: Primarily non-weight-bearing active joint exercises, isometric quadriceps contractions, etc.
   • Progression: Gradually increase the range of motion and duration according to pain tolerance and healing progress.
2. Mid-Phase Rehabilitation (around 6–8 weeks after fracture or surgery, depending on bone healing):
   • Frequency: 3–5 times per week.
   • Intensity: Moderate intensity; gradually allow partial weight-bearing, such as standing and walking training with the assistance of crutches.
   • Time: 15–20 minutes per session, progressively increasing to about 30 minutes.
   • Type: May include aquatic exercises, stationary cycling, and core stability training to reduce direct impact on the hip.
   • Progression: Gradual increase in weight-bearing with protective bracing, progressing to standing balance training.
3. Late-Phase Rehabilitation (12 weeks or more after fracture or surgery):
   • Frequency: 3–5 times per week, maintaining moderate intensity.
   • Intensity: Progressively return to near-normal activity levels; under professional guidance, light jogging or strength training may be introduced if appropriate.
   • Time: At least 30 minutes per session, alongside daily activities.
   • Type: Incorporate functional training such as balance exercises, low-impact plyometric drills, and hip and lower-limb strengthening.
   • Progression: Aim for a gradual return to athletic activities. If necessary, reduce high-impact activities and continue imaging follow-up.

Throughout the rehabilitation process, special attention should be paid to the growth characteristics of the child’s bones and overall bone health. Avoid strong impacts or excessive weight-bearing that may increase the risk of recurrent fractures. Regular imaging follow-up is recommended to evaluate any changes in the cyst and monitor bone healing.

Disclaimer: This report provides a reference for medical imaging analysis and does not replace in-person consultation or professional medical advice. Specific treatment plans should be individualized according to the patient’s actual condition under the guidance of a specialist.