Medical Imaging Analysis Report

I. Imaging Findings

Based on the provided X-ray and MRI images, a large protrusion is observed on the surface of a long bone (suspected femur) near the diaphysis, showing irregular thickening. The specific features are as follows:

• X-ray Findings: On the lateral wall of the diaphysis, radiolucent zones are interlaced with relatively dense shadows, forming an irregular protrusion contour. Local areas appear to have cartilaginous calcification (punctate or ring-shaped). The cortical bone seems to be involved to varying degrees and locally communicates with the medullary cavity.
• MRI Findings: The lesion extends into the soft tissue. On T1-weighted images, the cartilage cap appears low or intermediate in signal intensity; on T2-weighted images, certain high-signal areas (consistent with cartilaginous components) are evident. A soft tissue mass is visible, with unclear margins and heterogeneous signals in some regions.
• Pathological Images Suggest: Under the microscope, abundant abnormal chondrocytes are present within the cartilaginous tissue, with increased cell density, some cells exhibiting large or binucleated forms, and focal areas showing bone invasion or fibrous tissue bands replacing the normal bone marrow cavity.

Based on the imaging and histological evidence, the lesion demonstrates malignant potential, characterized by a thickened cartilage cap, irregular margins, and localized bone destruction with soft tissue involvement.

II. Possible Diagnoses

1. Chondrosarcoma:
   This is a common type of malignant transformation arising from a pre-existing osteochondroma (exostosis). It typically shows proliferative cartilaginous components on imaging, such as cartilaginous calcification, irregular bony destruction, and protrusions into the soft tissue.
2. Osteosarcoma:
   Malignant transformation can also occur in existing bony lesions, characterized by the formation of osteoid or bone-like tissue. Radiographic findings often include new bone formation and a positive Codman’s triangle. Osteosarcoma with cartilaginous components is also possible.
3. Benign Osteochondroma (Exostosis) without Malignant Change:
   If the lesion is a simple osteochondroma, it usually presents as continuous with the cortex and has a thin cartilage cap without significant pain. Malignant transformation is less likely if it has well-defined margins and minimal soft tissue involvement.

Given the above imaging and histological features, the most likely cause is malignant transformation from a benign osteochondroma, with chondrosarcoma being the most common malignant component.

III. Final Diagnosis

Considering the patient’s age (20 years), clinical symptoms, and the aforementioned imaging and pathological changes, the most likely diagnosis is: Osteochondroma (Exostosis) Malignant Transformation into Chondrosarcoma.

Although other sarcomas such as osteosarcoma should still be considered, the presence of abnormal chondrocytes and invasive cartilaginous features more closely aligns with the progression from an osteochondroma to chondrosarcoma. Further histological grading and pathological diagnosis may be needed to precisely determine the degree of differentiation and prognosis.

IV. Treatment Plan and Rehabilitation

1. Treatment Strategy

• Surgical Treatment: The first choice is usually wide or extended resection of the tumor, ensuring both the lesion and a safe margin are resected together. In cases where the tumor invades the soft tissues, a combined or more comprehensive soft tissue resection may be required.
• Adjuvant Therapy: For intermediate- to high-grade chondrosarcoma, postoperative radiotherapy or adjuvant chemotherapy may be considered, depending on the chondrosarcoma grade and pathological type.

2. Rehabilitation and Exercise Prescription

After surgery or treatment, a step-by-step rehabilitation plan can be established to facilitate limb function recovery and improve quality of life:

• Early Rehabilitation (0-2 Weeks Postoperative):
  • The focus is on maintaining basic limb function, preventing thrombosis, and avoiding muscle atrophy.
  • Light isometric muscle exercises (such as quadriceps tightening and relaxing) can be performed, along with limb elevation and gentle massage to promote circulation.
  • Depending on the physician’s approval and pain tolerance, the patient may practice ambulation with bracing or assistive devices (e.g., crutches) with partial weight-bearing.
• Mid-Term Rehabilitation (2-6 Weeks Postoperative):
  • Gradually increase the range of motion exercises, including passive joint movement and active-assisted exercises to improve joint mobility.
  • Initiate light to moderate strength training—such as ankle pumps or straight-leg raises in seated or supine positions. Progressively increase weight-bearing while closely monitoring pain and swelling.
  • Combine physical therapy modalities (heat, ultrasound, etc.) to enhance local blood circulation and promote soft tissue repair.
• Late Rehabilitation (6 Weeks Postoperative and Beyond):
  • If bone healing is satisfactory, and with physician clearance, gradually introduce higher-intensity weight-bearing activities and joint mobility exercises to restore daily functional activities (such as climbing stairs, balance training in standing position, etc.).
  • For patients with higher demands on motor function, more advanced functional training can be implemented, such as light jogging or cycling (ensuring proper bone healing and local stability).
  • Combine core muscle training to maintain overall coordination. Aquatic therapy or low-impact exercises may be included to improve endurance and reduce stress on the joint.

Throughout rehabilitation, please follow the FITT-VP principle (Frequency, Intensity, Time, Type, Progression, and Individualization), adjusting frequency and intensity based on the patient’s bone healing progress, muscle strength, and cardiopulmonary condition.

For patients with relatively fragile bone or extensive surgical resection, weight-bearing should be introduced gradually to prevent falls or local re-injury.

V. Disclaimer

This report is based solely on the provided imaging and limited clinical data. It is intended to serve as a reference for medical decision-making and should not replace an in-person consultation or the final opinion of a professional physician. If necessary, please consult a qualified medical institution for further examination and treatment.