ABSTRACT
Orbital mesenchymal chondrosarcoma, first described by Luis et. al in 1971, is a very rare tumor of characteristic histologic features. A 21-year-woman was admitted with a 4-month histoiry of rapidly progressive proptosis and visual disturbance. Right orbital exenteration was performed under the clinical diagnosis of orbital calcifying tumor. Grossly, the tumor presented as a multibloblated, circumscribed mass that measures 5.5 cm in the greatest dimentsion. Cut sections resembled ordinary chonrosarcoma. Microscopically, the tumor was composed of undifferentiated mesenchymal cells, interspersed nodules of well differentated cartilagenous tissue, areas of gradual transition from undifferentiated mesenchymal cells to cartilage, and hemangiopericytoma-like areas. A brief summary of the histopathological aspect of this tumor and a review of literature are presented.