1. Imaging Findings

Based on the provided X-ray images, the first, second, and third toes of the child's left foot are notably enlarged, showing asymmetric hypertrophy involving both soft tissues and the corresponding phalanges. Bone continuity is intact, with no visible fracture lines, and there are no marked abnormalities in the arrangement of trabeculae.
MRI images indicate a significant increase in fat-like signals within the enlarged toe soft tissues, alongside partial fibrous tissue proliferation, which is consistent with fat-fibrous tissue overgrowth. Overall, the lesion is localized to the affected toes of the forefoot, and no significant abnormal signals are observed in the surrounding skin or soft tissues.

2. Potential Diagnoses

1. Congenital Macrodactyly (including Macrodystrophia Lipomatosa)
   Characterized by unilateral or partial enlargement of the toes, often with persistent fatty and fibrous tissue overgrowth. This aligns with the imaging findings of increased fat signals and local hypertrophy.
2. Other Congenital Localized Overgrowth Syndromes
   Conditions such as Proteus syndrome or neurofibromatosis may show localized overgrowth, but they often present with other systemic manifestations or skin changes. In this case, the child shows no significant skin or neurological changes, making these syndromes less likely.
3. Congenital Lymphedema
   Typically presents with soft tissue swelling, sometimes with skin changes or pitting edema. However, there are no skin changes or pitting edema in this case, making it less consistent with this diagnosis.

3. Final Diagnosis

Considering the progressive enlargement of some toes of the left foot since birth, the characteristic fatty and fibrous tissue proliferation seen on imaging, and the absence of other systemic involvement, the most likely diagnosis is: Macrodystrophia Lipomatosa (Congenital Macrodactyly).

4. Treatment Plan and Rehabilitation

Given that the enlarged toes currently have relatively preserved function and there are no significant neurovascular symptoms, the primary treatment objectives are cosmetic improvement and prevention of further functional impairment. Specific plans are as follows:

1. Observation and Conservative Management:
   If the child's symptoms are mild, with no significant difficulties walking or wearing shoes, regular follow-ups can be conducted (e.g., X-ray or ultrasound/volume measurements every 6–12 months) to monitor toe growth. Maintain cleanliness of the local skin and proper foot care to prevent irritation or infection.
2. Surgical Intervention:
   If the lesion continues to enlarge, adversely affecting foot function or appearance, or if there is a risk of bone and joint complications, surgical debulking (potentially in multiple stages, along with soft tissue reconstruction) may be considered to preserve or improve foot function and appearance. Surgery should prioritize the protection of neurovascular structures and maintain proper foot alignment.

Rehabilitation and Exercise Prescription (FITT-VP Principle):
Within tolerable limits, to prevent foot function deterioration and support normal growth and development, moderate lower-limb functional exercises and full-body activities are recommended:

• Frequency: 2–3 times per week of light lower-limb targeted training, with normal preschool activities on other days.
• Intensity: Low intensity, such as gentle walking or simple balance exercises on soft mats or indoor floors, avoiding excessive load or pain in the foot.
• Time: Each session lasts about 15–20 minutes, gradually increasing to 30 minutes based on the child's comfort and foot tolerance.
• Type: Recommended activities on soft surfaces or shallow water (if possible), focusing on play-based training such as walking on a balance beam or light hopping on a soft mat. Encourage toe and foot joint activity, but avoid high-impact loading.
• Volume: Gradually increase the frequency and duration of activities as the child grows, but avoid fatigue or overloading the foot.
• Progression: As foot stability improves, the child may attempt more advanced balance exercises or light running games. Close observation of toe overgrowth and foot loading patterns is essential, and regular follow-up examinations are advised.

During this process, special attention should be paid to protecting foot alignment and joint mobility. If signs of foot fatigue, pain, or accelerated deformity become evident, seek medical advice promptly and adjust the exercise prescription accordingly.

5. Disclaimer

This report is based solely on the provided imaging and clinical information for reference purposes and does not replace an in-person consultation or professional medical advice. If you have any questions or if the condition changes, please consult a medical professional for further evaluation and treatment.