1. Imaging Findings

Based on the provided ultrasound, MRI, and chest CT images:

• In the superficial soft tissue of the shoulder (observed in the subcutaneous or fascial layer on imaging), there is a soft tissue mass with a relatively clear outline. It shows low-to-intermediate T1 signal and high T2 signal, with locally uneven internal signals suggesting possible necrosis or cystic changes.
• After contrast enhancement, moderate enhancement is observed in the peripheral and solid portions of the mass, while the central necrotic or cystic area shows no obvious enhancement.
• From the chest CT images, diffuse multiple small nodular shadows or lesions can be seen in both lungs, suggesting possible pulmonary metastases.
• Subsequent spinal MRI indicates no obvious signs of local bone destruction, but surrounding soft tissue changes warrant vigilance for local tumor invasion.

Based on the imaging features, the lesion in the shoulder soft tissue appears relatively well-defined. However, its signal characteristics are consistent with soft tissue sarcoma, particularly malignant tumors originating from smooth muscle or fibrous tissue.

2. Potential Diagnoses

Considering the patient is a 36-year-old female with a history of scleroderma, increased shoulder pain, and a visible soft tissue mass, in conjunction with the imaging features, the potential diagnoses include:

1. Leiomyosarcoma
   Primarily arising from soft tissue, leiomyosarcoma on MRI often appears as low-to-intermediate T1 signal and high T2 signal, frequently with necrotic areas and heterogeneous enhancement after contrast. Metastases may occur (commonly to the lungs, bones, etc.), matching the imaging presentation here.
2. Fibrosarcoma or Myofibrosarcoma
   These can present as soft tissue masses with high T2 signals and heterogeneous enhancement on MRI, but differentiation usually requires pathological diagnosis.
3. Rhabdomyosarcoma
   Relatively rare in adults, but still a differential diagnosis for soft tissue malignancies.
4. Metastatic Tumor
   If there is another primary tumor elsewhere in the body (e.g., breast cancer, renal cancer), soft tissue metastases can also occur. However, given the patient’s history, there is no clear evidence of another primary tumor, making this less likely.

In summary, the above potential diagnoses all require pathological biopsy for definitive confirmation.

3. Final Diagnosis

Based on the clinical presentation (chronic pain, limited mobility), MRI characteristics (low-to-intermediate T1 signal, high T2 signal, central necrosis or cystic changes, irregular enhancement), and suspicious pulmonary metastatic lesions, this case is most suggestive of leiomyosarcoma. Since the final diagnosis of soft tissue sarcoma relies on histological examination, a biopsy (needle or surgical) is recommended to obtain pathological evidence for a definitive conclusion.

4. Treatment Plan and Rehabilitation

4.1 Treatment Plan

• Surgical Treatment: For localized soft tissue sarcomas, the main treatment approach is wide excision, recommending a 3-5 cm margin of normal tissue. If the lesion is close to critical neurovascular structures, the aim is to achieve as complete a resection as possible while preserving function.
• Radiation Therapy: This can be used preoperatively or postoperatively, especially if obtaining sufficiently wide margins is difficult, to reduce the risk of local recurrence.
• Chemotherapy and Targeted Therapy: Decision-making depends on the tumor stage, pathological type, and metastasis. Certain soft tissue sarcomas may benefit from chemotherapy to control recurrence or slow disease progression. If specific susceptible genes or signaling abnormalities are identified, targeted therapy may be considered.
• Pulmonary Lesion Management: If pulmonary nodules are confirmed by imaging and pathology as metastatic lesions, management should be based on the patient’s overall condition, potentially including surgical resection, localized radiotherapy, or systemic treatments.

4.2 Rehabilitation and Exercise Prescription

During the postoperative or combined therapy phase, because of significant limitations in shoulder function and risk of pain, rehabilitation training should follow a step-by-step approach:

1. Early Recovery Phase (postoperative or early treatment phase, soft tissue healing period):
   • Focus on passive joint mobility and gentle active exercises, avoiding large shoulder movements to prevent tension on the surgical incision or soft tissue.
   • Each session lasts about 10-15 minutes, 2-3 times daily, to reduce joint stiffness and improve blood circulation.
2. Mid-Recovery Phase (approximately 4-6 weeks after stable wound healing):
   • Under the guidance of a professional therapist, increase gentle shoulder and upper limb muscle-strengthening exercises, such as resistance band training and isometric shoulder exercises.
   • Gradually increase exercise intensity to a moderate level, extending each session to about 20-30 minutes, 1-2 times daily.
3. Late Functional Reconstruction Phase (2-3 months or more after surgery):
   • Aim to restore shoulder function and daily activity capabilities. Gradually introduce functional exercises such as lifting, dumbbell workouts, or light resistance exercises.
   • Increase exercise intensity to a moderate-to-high level, ensuring pain is tolerable and monitoring joint and soft tissue responses.

Throughout the rehabilitation process, closely monitor shoulder pain, swelling, skin condition, and overall health status, and adjust accordingly. Patients with scleroderma need to pay additional attention to maintaining skin elasticity and joint mobility to prevent severe contractures.

Disclaimer

This report is based solely on the current imaging and the provided medical history for a preliminary analysis and does not replace face-to-face consultation or professional medical advice. Specific diagnosis and treatment plans require further pathology, laboratory tests, and clinical evaluation. If you have any questions, please consult a professional physician promptly.