Low-grade fibromyxoid sarcoma versus myxofibrosarcoma in extremities and trunk:a comparative analysis of clinicopathological features

Purpose To investigate the clinicopathological features,behavior,diagnosis and differential diagnosis of low-grade fibromyxoid sarcoma (LGFMS) and myxofibrosarcoma (MFS) in trunk and extremites.Methods Five cases of LGFMS were analyzed and compared with 4 cases of MFS with respect to clinical information,macroscopy,histology,immunohistochemical markers and prognosis.Results The two entities could be distinguished on histological grounds.LGFMS was composed of bland spindle cells with alternating myxoid and fibrous stroma.Tumor cytological atypia was absent,and no tumor necrosis was observed in any of LGFMS.MFS was characterized by the presence of prominent elongated,curvilinear capillaries and psudolipoblasts,accompanied by an abundant myxoid matrix.It had no expensive solid areas,And tumor necrosis was observed.The two entities had differentiation in immunohistochemical markers,tumor location and patient's years.Conclusions LGFMS is a rare tumor,and different from MFS in clinicopathological features and behaviors.LGFMS has better prognosis than FMS.