1. Imaging Findings

Based on the cranial MRI, chest CT, and PET-CT images provided by the patient, the following major imaging characteristics are observed:

• MRI (Cranial): In the skull base and petrous part of the temporal bone, there is evidence of localized bone destruction or occupying lesions. In certain areas, T1-weighted sequences show low signal intensity, while T2-weighted sequences exhibit isointense or slightly hyperintense signals, with uniform enhancement after contrast administration. Suspected soft tissue components in the skull base and parts of the cranium suggest possible osteolytic lesions with local extramedullary extension.
• CT (Chest): Varying degrees of reduced bone density and local osteolytic lesions are observed in the thoracic vertebrae and ribs. In some areas, lesions appear to breach the cortex externally. Although no evident fracture lines are visible on the CT images, there is a potential risk of fracture. A possible sternal puncture or biopsy trajectory is also indicated.
• PET-CT: Multiple skeletal hypermetabolic lesions are noted, especially affecting the spine, ribs, and skull in the axial skeleton, indicating highly metabolic osteolytic changes consistent with multifocal lesions.

Laboratory results show decreased hemoglobin (Hb) (9 g/dL) and significantly elevated serum calcium (15 mg/dL), which is considered severe hypercalcemia (generally >14 mg/dL is regarded as severe). Combined with clinical symptoms such as headache and diplopia, these findings suggest the possibility of a systemic disease involving the skull base and cranial nerves.

2. Potential Diagnoses

Based on the above imaging findings, along with the patient’s laboratory results and clinical symptoms, the following diagnoses or differentials are possible:

1. Multiple Myeloma
   Rationale: Commonly seen in middle-aged and older patients, often presenting with anemia, hypercalcemia, osteolytic bone destruction, and bone pain. Serum protein electrophoresis may show elevated M protein. MRI can reveal bone marrow infiltration and local soft tissue masses.
2. Metastatic Bone Tumor
   Rationale: Osteolytic lesions can also occur in bony metastases from certain solid tumors (e.g., breast cancer, lung cancer). However, identification of a primary lesion, lack of specific M protein elevation, and consideration of clinical and immunological tests are necessary for comprehensive diagnosis.
3. Lymphoma Bone Invasion
   Rationale: Certain types of non-Hodgkin’s lymphoma may involve the bone. Imaging can sometimes display mixed osteolytic and sclerotic features. Pathological biopsy is required for differentiation.

3. Final Diagnosis

Taking into account the clinical presentation (anemia, headache, diplopia), laboratory findings (marked hypercalcemia, reduced hemoglobin), imaging characteristics (multifocal osteolytic bone destruction, evidence of bone marrow infiltration), as well as hints from electrophoresis and bone marrow aspiration results, the most likely diagnosis is:

Multiple Myeloma.

If there is still uncertainty or a need for special subtype clarification, further bone marrow biopsy and tests such as immunofixation electrophoresis and free light chain assays can be performed to confirm the diagnosis and assess staging.

4. Treatment Plan and Rehabilitation

(1) Treatment Plan

• Chemotherapy and Targeted Therapy: Combination regimens including alkylating agents, proteasome inhibitors, and immunomodulators can significantly improve disease progression.
• Supportive Care: This includes correction of hypercalcemia (intravenous fluids, bisphosphonates), symptomatic management of anemia, and infection prevention.
• Management of Bone-related Complications: For sites with evident structural damage and a high risk of pathological fractures, interventions such as vertebroplasty, surgical fixation, or radiotherapy may be considered to stabilize local lesions.
• Hematopoietic Stem Cell Transplantation: Autologous stem cell transplantation may be an option for eligible patients to improve outcomes.

(2) Rehabilitation and Exercise Prescription

• Rehabilitation Goals: Alleviate bone pain, enhance activities of daily living, prevent further fractures, and improve overall functional status.
• Exercise Prescription Principles (FITT-VP):
• Frequency: 3-5 times per week, adjusted according to the patient’s endurance and pain level.
• Intensity: Start with low intensity (e.g., slow walking, stretching), avoiding excessive weight-bearing or vigorous movements.
• Time: 15-30 minutes per session initially, gradually increasing to 30-45 minutes as tolerated.
• Type: Emphasize low-impact aerobic activities (such as walking or using a stationary bike), supplemented by low-intensity resistance training (using resistance bands or light dumbbells). High-load or spine-jarring activities should be avoided.
• Progression: Increase exercise duration and intensity slightly every 2-4 weeks, provided there is no cyanosis, severe dyspnea, or significant worsening of bone pain.
• Volume and Personalization: Begin with a smaller total exercise volume, then adjust individually as the patient recovers. Combine with nutritional support to prevent exacerbation of hypoproteinemia or anemia.
• Safety Precautions: Given the patient’s fragile bones, falls and high-impact exercises must be avoided. If severe pain, dizziness, or fatigue occurs, exercise should be stopped immediately, and medical consultation is advised.

Disclaimer

This report is a reference medical analysis based on the limited information provided and cannot replace a professional consultation or a physician’s opinion. Specific treatment and rehabilitation plans must be tailored to the patient’s actual clinical condition under the guidance of a qualified medical professional.