Primary orbital dedifferentiated liposarcoma with leiomyosarcomatous and low-grade osteosarcomatous differentiation

Liposarcoma originating in the orbit is extremely rare. Herein, we report a dedifferentiated lipo sarcoma arising from the orbit of a Chinese woman. This patient underwent tumor resection at the age of 56 years and recurred 50 months after the initial resection. Histologically, the initial lesion exhibited features of well-differentiated liposarcoma with focal areas of well-differentiated ossified component. The recurrent tumor predominantly consisted of spindle cell sarcoma, low-grade ossified component, and a small amount of well-differentiated liposarcoma. Immunohistochemically, the spindle cell sarcomatous component of the recurrent lesion exhibited strong positivity for desmin, smooth muscle actin, and H-caldesmon. Both the original and recurrent lesions showed strong positivity for p16, MDM2, and CDK4. Fluorescence in situ hybridization revealed MDM2 gene amplification in all of the tumor components. To the best of our knowledge, this is the first published example of orbital dedifferentiated liposarcoma exhibiting leiomyosarcomatous and low-grade osteosarcomatous differentiation.