ABSTRACT
AIM: To investigate the clinicopathological features of orbit primary liposarcoma. METHODS: By means of histological, ultrastructural and immunohistochemical studies, the clinical and pathological features of two cases of orbit primary liposarcoma were analyzed and compared with 6 cases of primary retroperitoneum liposarcoma. RESULTS: Two cases of orbit primary liposarcoma were young persons. The majority of cases of primary retroperitoneum liposarcoma were aged over 40 years. The tumors were located at the retrobulbar region, and involved the wall of eyeball and optic nerve. The tumor cells of case 1 were round, with abundant eosinophilic granules in the cytoplasm, and there were lipoblasts in the tumor cells of two cases. Local recurrence following excision occurred in case 2.Immunohistochemical expression of S100 protein was positive in all cases, and CK (AE1/AE3), desmin, MyoD1, melanoma were negative. Ultrastructure observation showed lipid drops in the tumor cells in case 2 of orbit primary liposarcoma. CONCLUSION: Primary liposarcoma of the orbit may recur.The diagnosis was based on histological,ultrastruc-tural observation and immunohistochemical staining.