metastatic myxoid liposarcomamyxoid liposarcoma histologymyxoid liposarcoma pathologymyxoid liposarcoma prognosismyxoid liposarcoma cancermyxoid liposarcoma pathology outlinesmyxoid round cell liposarcomamyxoid liposarcoma survival ratemyxoid sarcoma prognosisliposarcoma photosmyxoid sarcoma cancermyxoid cells