Mesenchymal chondrosarcoma is a highly malignant and extremely rare tumor of the orbit: only 18 cases have been reported to date. We report a case of spheno-orbital mesenchymal chondrosarcoma in a 36-year-old woman presented with a 4-month history of progressive left exophthalmia and temporal mass. A CT-scan of the orbit and MRI showed a spheno-orbital mass, with temporal fossa extension, fed by the internal maxillary artery visible on cerebral angiography. Surgery via a transcranial, left frontotemporozygomatic approach after selective embolization enabled subtotal removal. Definitive histologic examination revealed mesenchymal chondrosarcoma. Postoperatively, exophthalmia spectacularly regressed. We report our clinical findings and present a review of the literature.