BACKGROUNDExtraskeletal mesenchymal chondrosarcoma (MCS) is relatively uncommon. Orbital location is extremely rare: only 16 cases have been reported until now. We report a case of extraskeletal mesenchymal chondrosarcoma in a 27-year-old man and review the literature on its manifestations and management.CASE REPORTThis patient had a 2-year history of progressive proptosis of the right eye. Skull X-ray and CT scan showed intra-orbital calcification and a large lesion in the upper right orbit. He was operated three times because of recurrence of the tumor. The last recurrence was observed to have extension to the intracranial region, detected on MRI and CT scan. This secondary extension of the tumor to the intracranial region has not been previously reported. Immunohistochemical analysis for S-100 protein showed focal positivity.CONCLUSIONMesenchymal chondrosarcoma of the orbit is rare, and secondary extension to the intacranial region has not previously been reported.