Medical Imaging Analysis Report

I. Imaging Findings

Based on the provided ultrasound and MRI results, the lesion is located in the subcutaneous tissue of the mid-left thigh. It appears solid and irregular in shape with the following characteristics:

• Ultrasound: Shows a heterogeneous hypoechoic mass with abundant internal blood flow signals and posterior acoustic enhancement. The actual depth range of the lesion is difficult to accurately determine by ultrasound.
• MRI:
  • On the T1-weighted images (T1-WI), the signal is relatively low, with regions of heterogeneous signal at the margins, suggesting possible necrosis or cystic changes inside.
  • On the T2-weighted (T2-WI) and PD images, the lesion shows markedly high signal intensity, with focal high-signal areas indicating complex internal components.
  • The lesion is mainly located in the subcutaneous layer, with an apparent compressive or potentially infiltrative effect toward the deeper soft tissues. However, MRI shows a relatively clear boundary with the muscle layer, and no obvious muscle invasion is observed.
  • After contrast enhancement, the lesion shows heterogeneous enhancement, consistent with common characteristics of soft tissue tumors.

The overall assessment indicates locally infiltrative growth with a close relationship to surrounding tissues, and the skin surface shows ulceration and bleeding changes.

II. Differential Diagnosis

Taking into account the patient’s history (a 57-year-old male with a long-standing subcutaneous mass in the left thigh, recently exhibiting skin ulceration and bleeding) and the imaging presentation, the following should be considered:

1. Dermatofibrosarcoma Protuberans (DFSP): This tumor commonly arises in the skin and subcutaneous tissues, grows slowly but has locally invasive potential. On MRI, it often appears as a solid mass with low T1 signal and high T2 signal, and may exhibit necrosis, cystic changes, and heterogeneous enhancement. Clinically, tumor enlargement, bleeding, or ulcer formation may occur.
2. Other Soft Tissue Sarcomas: For example, malignant fibrous histiocytoma or liposarcoma. These can also present as solid soft tissue masses with surface ulceration. Histopathological analysis and immunohistochemistry are needed for definitive differentiation.
3. Deep Hemangioma or Angiosarcoma: An abundant vascular supply may be seen on ultrasound and MRI, but the imaging morphology and enhancement patterns often differ slightly. Pathological examination is required for clarification.

III. Final Diagnosis

Considering the patient’s age, the longstanding presence of the mass, recent skin ulceration and bleeding, and the subcutaneous infiltrative growth pattern on imaging along with MRI signal characteristics, the most likely diagnosis is Dermatofibrosarcoma Protuberans (DFSP). Since definitive diagnosis requires pathological and immunohistochemical confirmation, further postoperative histological and immunohistochemical examinations are essential to establish the diagnosis.

IV. Treatment Plan and Rehabilitation

1. Treatment Plan

• Surgical Resection: The primary treatment for DFSP is surgery, requiring adequate and complete tumor excision. If MRI suggests a distinguishable safe margin between the tumor and the muscle layer, every effort should be made to preserve muscle function, but adequate surgical margins must be ensured.
• Other Treatments: For cases with unclear margins or postoperative recurrence, adjuvant radiotherapy or molecular targeted therapy (e.g., tyrosine kinase inhibitors) may be considered, depending on pathological staging and individual circumstances.

2. Rehabilitation and Exercise Prescription

Following surgical resection and completion of treatment, the rehabilitation program should follow these general principles:

• Early Stage (1–2 weeks post-operation):
  • Focus on protective training, ensuring basic maintenance of limb mobility and muscle strength.
  • Gentle active or passive joint movements can be performed, avoiding excessive traction on the surgical area. Pain should remain within a tolerable range.
• Middle Stage (2–6 weeks post-operation):
  • When the wound has healed well, begin low-intensity weight-bearing exercises, such as straight leg raises and isometric quadriceps strengthening.
  • Gradually increase the range and duration of activities, 2–3 times daily, 15–20 minutes each session, while closely monitoring for swelling or pain.
• Late Stage (6 weeks post-operation and beyond):
  • Progressively return to regular muscle strengthening and functional exercises according to individual needs, including walking and light strength training.
  • Following the FITT-VP principle, gradually increase exercise frequency (3–5 times per week), intensity (from mild to moderate), and duration (gradually up to 30 minutes or more), with low-impact options like swimming or using a stationary bike. Monitor the surgical area closely.
  • If there is limited weight-bearing capacity in the lower limb, targeted training under the guidance of a rehabilitation therapist or specialist is recommended to ensure safety.

Throughout the rehabilitation process, consider the patient’s overall condition, including any comorbidities (e.g., compromised cardiopulmonary function or low bone density), adjusting exercise intensity and scope accordingly to ensure a safe, individualized program.

V. Disclaimer

This report is based on the current imaging and clinical information provided, offering a reference analysis only. It does not replace in-person consultation or the treatment advice of a qualified medical professional. Patients should follow their specialty physician’s guidance, considering personal medical history, surgical results, and pathological findings, to determine the appropriate course of treatment.