myxoid sarcoma prognosismyxoid sarcoma cancermyxoid sarcoma pathology outlinesmyxoid spindle cell sarcomamyxoid liposarcoma treatmentmyxoid tumorsmyxoid liposarcoma metastasismyxoid liposarcoma chemotherapyextraskeletal myxoid chondrosarcomamyxoid liposarcoma pathologymyxoid liposarcoma prognosismyxoid dermatofibrosarcoma protuberans