Presentation
The patient presented with worsening bi-frontal peri-orbital headaches for a year, which were initially attributed to migraine. After one year, the patient started to experience diplopia with blurry vision.
Patient Data
CT of the orbits with IV contrast shows an intraconal left superolateral orbital lesion with central coarse calcifications. There is no bony erosion or intracranial extension.
MRI of the orbits without and with IV contrast shows a left orbit retrobulbar lesion which is T1 hypointense and T2 hypointense. There is enhancement of the mass, greatest peripherally. Focal low T2 signal in the mass likely corresponds to calcification seen on CT. The mass abuts the superior rectus muscle and lateral rectus muscle as well as the superior ophthalmic vein. The optic nerve is deviated slightly to the right by the mass, with normal / symmetric dural sheath fluid. There is no involvement of the lacrimal gland. No exophthalmos is evident. No intracranial extension is seen.
MRI of the brain without and with IV contrast confirms the findings seen on the MRI of the orbits, showing an enhancing intraconal lesion. It also shows blooming artifact in the lesion on the GRE sequence consistent with calcifications. There is no definite diffusion restriction, although this may be limited due to the calcifications. Feeding/draining vessels are noted but MRA and MRV sequences (at the end) do not suggest aneurysm or vascular malformation. No brain lesions are seen.
Case Discussion
The left orbital mass was surgically resected by ophthalmology. The mass fragmented during resection.
Pathology demonstrated high-grade malignant small round cell neoplasm with abrupt osteocartilaginous differentiation. The tumor extended into inked margins. Tumor cells were focally positive for desmin and S100 (cartilage), and weakly positive for CD34, keratins, nuclear beta-catenin, and synaptophysin. The features were diagnostic of mesenchymal chondrosarcoma (extraskeletal origin).
The patient subsequently underwent 12 cycles of chemotherapy (vincristine, doxorubicin, and cyclophosphamide (VDC) alternating with ifosfamide and etoposide (IE)). Follow-up orbit MRIs have shown no evidence of residual or recurrent tumor. PET/CT and chest CT showed no definite evidence of metastatic disease.
Case co-author: Xhulio Arolli, BS, MS (Stritch School of Medicine)
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