Medical Imaging Analysis Report

I. Imaging Findings

Based on the provided X-ray, CT, and MRI images, the following findings are observed:

• Multiple osteolytic lesions affecting the metatarsal bones, tarsal bones, talus, etc. in both feet (especially the right foot). Some present as “moth-eaten” or diffuse bone destruction, and varying degrees of cortical destruction and expansion are noted.
• CT images show signs of soft tissue infiltration. The lesion boundaries are relatively indistinct with no obvious periosteal reaction.
• On MRI T1-weighted images, the lesions appear slightly low or low signal; on T2-weighted images, some lesions exhibit relatively low signal (possibly related to high cellular density). Prominent high signal on STIR sequences suggests active lesions or bone marrow edema.
• Post-contrast enhancement reveals multiple bone and soft tissue enhancements. The margins are not well-defined, and local “encasement” can be observed, indicating tumor extension through the cortex but without complete destruction of the bone contour.
• In combination with PET-CT findings (if available), corresponding hypermetabolic lesions can be observed, further suggesting systemic involvement or multiple affected areas.

II. Possible Diagnoses

Taking into account the patient’s clinical symptoms (night sweats, weight loss, bone pain, etc.) and imaging features, the following differential diagnoses are considered:

1. Primary or Multiple Bone Lymphoma
   Description: The patient presents “B symptoms” (fever, night sweats, weight loss), with imaging showing bone destruction and soft tissue “encasement.” These findings can be consistent with diffuse large B-cell lymphoma.
2. Metastatic Bone Tumor
   Description: Generally presents with multiple osteolytic lesions, but an identifiable primary lesion should be determined. The patient has no history of malignancy or other clues, so further differentiation is required.
3. Multiple Myeloma
   Description: Frequently exhibits osteolytic lesions and systemic symptoms. The presence of abnormal M protein can support this diagnosis, but in this case, histopathology is more indicative of lymphoma.
4. Ewing Sarcoma or Osteosarcoma
   Description: Commonly seen in children and adolescents, often with mixed osteolytic and osteoblastic lesions plus more apparent periosteal reactions. The patient’s clinical age and imaging features do not strongly support these diagnoses.

III. Final Diagnosis

Considering the patient’s age, clinical symptoms (persistent bone pain, night sweats, weight loss as “B symptoms”), imaging features (multiple bone destructions with soft tissue involvement but lacking significant periosteal reaction), and histopathological evidence of CD20-positive diffuse large B-cell lymphoma, the most likely diagnosis is:

Primary Bone Lymphoma (Diffuse Large B-Cell Lymphoma).

Confirmation generally requires pathological examination (as done in this case), and exclusion of other causes to finalize the diagnosis.

IV. Treatment Plan and Rehabilitation

Comprehensive treatment options for primary bone lymphoma (diffuse large B-cell lymphoma) include:

• Chemotherapy and Immunotherapy: Commonly based on the R-CHOP regimen (rituximab plus chemotherapy). The specific drug regimen should be chosen according to the patient’s general condition and laboratory results.
• Radiotherapy: Can be combined with local radiotherapy for better local control of the lesion.
• Bone Marrow or Stem Cell Transplantation: If the disease is extensive or there is a high risk of relapse after first-line therapy, autologous stem cell transplantation may be considered.
• Supportive Care: Includes pain management, correction of anemia, and management of infections, among others.

Since the patient’s bone structure has been compromised by the tumor, rehabilitation exercises should be planned with caution to avoid fracture risk. Exercise and rehabilitation suggestions should follow the FITT-VP principle:

• Frequency: Depending on the stability of the patient’s condition, low-intensity sessions can be arranged 2–3 times per week. If the patient’s physical strength decreases during treatment, the frequency can be reduced accordingly.
• Intensity: Recommended intensity ranges from light to moderate, including gentle joint movements, walking, and lower limb strengthening using resistance bands or water-based exercises to reduce stress. Avoid high-impact or high-load activities.
• Time: Each session can last 20–30 minutes, potentially divided into shorter segments based on the patient’s tolerance. Prolonged strain should be avoided.
• Type: Focus on range-of-motion exercises, core strengthening, and safe lower extremity training. Balance training and hydrotherapy under the guidance of a physical therapist may also be incorporated.
• Volume & Progression: Gradually increase duration and intensity according to the patient’s tolerance to treatment and bone healing status. Early stages should emphasize gentle, steady exercises, transitioning to moderate intensity once bone lesions are under control and stable.

Throughout this process, closely monitor changes in bone pain, joint function, and overall physical status. Adjust the treatment and rehabilitation schedule as needed. Any acute severe pain or newly emerging lesions should prompt immediate medical consultation.