Soft tissue sarcoma is a type of cancer that originates from mesenchymal tissue and typically displays symptoms in later stages. Undifferentiated pleomorphic sarcoma is a subtype of soft tissue sarcoma that can be found in any body part. This case study discusses a 62-year-old patient diagnosed with pleomorphic sarcoma in the thigh. Soft tissue tumors can pose a problem if they grow and become malignant. Various examinations are conducted to diagnose sarcoma, including physical examination, ultrasound, MRI, or CT scan. A biopsy is necessary to make a definitive diagnosis of sarcoma and provides information about the subtype of sarcoma and its grade. The treatment approach for bone malignancies typically involves excision with wide margins, chemotherapy, and radiation therapy. Radical extirpation of the tumor is critical for the cure of soft tissue sarcomas in the extremities.