Abstract
BACKGROUND: Undifferentiated pleomorphic sarcomas, also known as spindle cell sarcomas, are a relatively uncommon subtype of soft tissue sarcomas in clinical practice. CASE SUMMARY: We present a case report of a 69-year-old female patient who was diagnosed with undifferentiated spindle cell soft tissue sarcoma on her left thigh. Surgical excision was initially performed, but the patient experienced a local recurrence following multiple surgeries and radioactive particle implantations. High-intensity focused ultrasound (HIFU) was subsequently administered, resulting in complete ablation of the sarcoma without any significant complications other than bone damage at the treated site. However, approximately four months later, the patient experienced a broken lesion at the original location. After further diagnostic workup, the patient underwent additional surgery and is currently stable with a good quality of life. CONCLUSION: HIFU has shown positive outcomes in achieving local control of limb spindle cell sarcoma, making it an effective non-invasive treatment option.