1. Imaging Findings

Based on the MRI and CT images of the cervical spine provided by the patient, a noticeable expansive lesion can be observed in the cervical vertebral body, exhibiting a “mini-brain” appearance on imaging. The specific features are as follows:

• Lesion Location and Morphology: The lesion is located in the cervical vertebral body (primarily involving certain segments of the cervical spine, as deduced from the images), presenting with expansion, bone destruction, and irregular local structural changes.
• Density/Signal Changes:
  • CT Findings: An enlarged lytic lesion is seen, with localized thickening of the vertebral cortical bone maintaining some of its shape, forming a “thick bony trabeculae” structure.
  • MRI Findings: On T1-weighted images, the lesion appears hypointense; on T2/STIR-weighted images, it appears hyperintense, with moderate to marked enhancement observed inside and around the lesion.
• Involvement of Surrounding Tissues: The lesion leads to weakened local vertebral structure, with compression or invasion of the adjacent spinal canal, resulting in varying degrees of spinal cord compression. A mass-like change can also be seen in the soft tissue.

2. Potential Diagnoses

Considering the patient’s age, symptoms (neck pain and quadriparesis triggered by minor trauma), and imaging findings, the following differential diagnoses can be taken into account:

• Lytic Metastasis: Most metastatic tumors can present lytic changes and typically progress quickly. The “thick cortical trabeculae” or “mini-brain” appearance is not commonly noted.
• Multiple Myeloma/Solitary Plasmacytoma (Osseous Plasmacytoma): Typical manifestations include expansive lytic lesions with well-defined margins, usually low signal intensity on T1-weighted images, and associated soft tissue masses. The distinct “mini-brain” appearance is characteristic of solitary plasmacytoma, caused by thickened trabeculae in the vertebral body.
• Other Primary Bone Tumors (e.g., Chordoma, Giant Cell Tumor): They may also show expansive changes with lytic destruction, but their common locations and imaging features differ from osseous plasmacytoma (e.g., chordoma often occurs in the clivus or sacrum; giant cell tumors typically occur at epiphyseal regions of long bones). Their signal characteristics vary as well.
• Infectious Lesions (e.g., Osteomyelitis, Spinal Tuberculosis): These can cause bone destruction and soft tissue masses but generally involve the paravertebral region or intervertebral discs, showing prominent inflammatory signs and elevated clinical infection markers.

3. Final Diagnosis

Combining clinical information (a middle-aged or elderly male patient with cervical spine lesion and quadriparesis after minor trauma), lab results, biopsy (pathological confirmation), and imaging findings (the characteristic “mini-brain” sign), the most likely diagnosis is:

Solitary Plasmacytoma of the Cervical Spine (Osseous Plasmacytoma of the Vertebral Body).

If pathological biopsy has confirmed the diagnosis, further differentiation is unnecessary. If there is suspicion of progression or other systemic involvement in the future, evaluation for multiple myeloma is advised.

4. Treatment Plan and Rehabilitation

For patients diagnosed with osseous plasmacytoma, the following treatment and rehabilitation considerations may be applied:

1. Treatment Strategy
   • Radiation Therapy: For spinal solitary plasmacytoma, local radiation therapy can effectively control the lesion and relieve spinal cord compression. If significant neurological compromise is evident, timely intervention is necessary.
   • Surgical Intervention: If there is severe vertebral structural damage or substantial spinal cord compression, or if instability persists after radiation, decompression with internal fixation can be considered to stabilize the spine and relieve pressure.
   • Pharmacotherapy: Some patients may require systemic therapy (such as chemotherapy or novel anti-myeloma agents) based on hematologic evaluation to prevent disease progression or transformation into multiple myeloma.
2. Rehabilitation and Exercise Prescription
   • Rehabilitation Goals: Alleviate limb weakness caused by spinal cord or nerve root compression, enhance cervical spine stability, and prevent secondary muscle atrophy and osteoporosis.
   • FITT-VP Principle Example:
     • Frequency: Begin with moderate rehabilitation exercises 2-3 times per week in the early stage, gradually increasing to 3-5 times per week as function improves.
     • Intensity: Light to moderate intensity (around 50-60% of perceived exertion), avoiding strenuous or rapid head and neck movements.
     • Time: 20-30 minutes per session, adjusted based on tolerance. Sessions can be divided into segments, ensuring adequate rest.
     • Type: Gentle stretching exercises for the neck and shoulders, light-resistance or isometric exercises for the upper limbs and core muscles, supplemented with basic walking training.
     • Volume: Determined by professional assessment of muscle strength and range of motion, with a gradual increase in total exercise volume.
     • Progression: As neck and limb strength and endurance improve, incrementally increase training intensity and duration while closely monitoring for pain or neurologic symptoms.
   • Safety Considerations: Avoid excessive cervical movement and loading to prevent additional injury. If increased pain, numbness, weakness, or any other discomfort occurs, stop training immediately and seek re-evaluation.

5. Disclaimer

The above analysis is for reference only and does not substitute for an in-person consultation or professional medical advice. Specific treatment and rehabilitation plans should be tailored to the patient’s individual condition and carried out under the guidance of qualified physicians and rehabilitation therapists.