Abstract
Malignant mesenchymal tumors are a diverse group of aggressive cancers originating from mesenchymal cells in connective tissues such as bone, muscle, cartilage, and fat. These tumors often invade surrounding tissues and metastasize to distant organs, posing significant treatment challenges. Among them, malignant mesenchymal tumors located in the distal femur are particularly rare, with limited reports detailing effective surgical and functional reconstruction strategies following wide resection. This case report focuses on the treatment of a distal femoral malignant mesenchymal tumor managed at our clinic, where wide resection was followed by reconstruction using a tumor resection prosthesis and extensor mechanism transfer. The report highlights the innovative surgical technique employed to restore extensor function while maintaining structural integrity, addressing a critical gap in the literature. By sharing insights into this approach, this report aims to contribute to the growing body of knowledge on limb salvage surgery and improve outcomes for patients with similar complex conditions.