1. Imaging Findings

Based on the provided pelvic X-ray, CT, and MRI images, there are significant abnormal changes involving the left iliac bone and pubic ramus:

• The anteroposterior pelvic X-ray shows a comminuted fracture of the left iliac bone and pubic ramus, with local bone destruction and disorganized trabecular patterns.
• CT images suggest a lytic lesion in the affected area, with some regions showing sclerotic changes and irregular high-density areas. There is disruption of the cortical bone continuity, and the surrounding soft tissue may be involved.
• MRI shows low signal intensity on T1WI and high signal intensity on T2WI in the corresponding area, with obvious enhancement, indicating possible tumor infiltration into the bone marrow and soft tissue. Local soft tissue swelling is noted, with a relatively extensive area of involvement.

2. Potential Diagnoses

Combining the patient’s age of 71, history of diabetes, the imaging findings described above, and clinical symptoms (limping for one month), the following possible diagnoses are suggested:

1. Bone lymphoma (especially Non-Hodgkin’s lymphoma):
   Seen more often in middle-aged to elderly patients, can present with osteolytic or mixed destructive lesions. Soft tissue involvement is common, and imaging may show low density or high signal changes.
2. Metastatic lesion:
   Metastases from malignancies such as breast cancer, lung cancer, or prostate cancer can cause bone destruction, sclerosis, or mixed changes.
3. Multiple myeloma:
   Common in older adults, usually shows osteolytic destruction. On MRI, there can be diffuse or focal low T1, high T2 signal changes in bone marrow. Further tests such as serum protein electrophoresis would help differentiate.
4. Bone infection (chronic osteomyelitis):
   Typically presents with pain, signs of infection, or local skin changes. MRI findings can demonstrate inflammatory changes, and clinically it often associates with elevated white blood cell count or local fever.

3. Final Diagnosis

Taking into account the patient’s age, sex, symptom profile, past medical history of diabetes, imaging findings, and subsequent diagnostic tests (including histopathology from biopsy), the most likely diagnosis is:

Non-Hodgkin’s Lymphoma (primary bone or with bone involvement)

The patient has received CHOP chemotherapy combined with Rituximab and local radiotherapy to relieve pain and control tumor burden, consistent with standard treatment protocols for lymphoma.

4. Treatment Plan and Rehabilitation

4.1 Overview of Treatment Strategy

• Chemotherapy + Targeted Therapy: CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) combined with Rituximab is a common regimen for Non-Hodgkin’s lymphoma and can effectively control disease progression.
• Radiotherapy: Targeting the local lesion to reduce pain and control the local tumor.
• Surgical Treatment: For those at risk of unstable fractures or pathological fractures, internal fixation or reconstructive surgery may be considered. However, in this case, due to the high risk of infection and possible prosthesis loosening, a complete hip replacement was not performed.
• Supportive Medical Care: Includes blood glucose control, infection prevention, calcium and vitamin D supplementation to reduce complications.

4.2 Rehabilitation and Exercise Prescription

During and after chemo- and radiotherapy, the rehabilitation plan should integrate the patient’s bone condition, response to tumor treatment, and overall status, with a gradual progression.

1. Initial Stage (Postoperative or Acute Treatment Phase):
   • The main goals are to prevent muscle atrophy and maintain joint range of motion. Bed-based active or passive exercises may be used.
   • Within tolerable pain levels and fracture risk limitations, perform gentle range-of-motion exercises (e.g., ankle pump, mild knee flexion/extension) and resistance exercises (e.g., low-intensity stretching with a resistance band).
2. Intermediate Stage (Rehabilitation Adaptation Phase):
   • Under professional supervision, perform sitting and standing balance training to strengthen core and lower limb muscles, avoiding excessive load.
   • Gradually increase exercise frequency to 3–4 times per week, with each session lasting about 20–30 minutes at a light to moderate intensity (RPE around 9–11).
3. Late Stage (Functional Consolidation Phase):
   • Once fracture healing is confirmed and the tumor is well-controlled, moderate weight-bearing exercises such as walking or light cycling can be introduced, while monitoring pain and fatigue.
   • If joint function permits, water-based exercises (swimming or aquatic walking) can be considered to reduce load and improve cardiopulmonary function.
   • Exercise frequency may be increased to 4–5 times per week, each session 30–40 minutes, maintaining moderate intensity (RPE 10–13). Avoid high-impact activities.

Throughout the rehabilitation process, close monitoring of skeletal stability and pain levels is essential. Regular imaging and laboratory tests should be performed, and the rehabilitation plan adjusted as needed according to the patient’s condition.

Disclaimer:

The above report is based on the available information for reference only and cannot replace in-person consultation or the opinion of a professional physician. If you have any questions or changes in your condition, please contact a specialist promptly.