Primary tumors of orbital bone are rare, constituting up to 2% of all orbital masses.1 Chondromyxoid fibroma (CMF) is one of the least common tumors of bone, composing less than 1% of bone tumors and less than 2% of benign bone tumors.2,3 Apart from brief case reports,4-6 orbital CMF has not been clearly documented in the ophthalmic literature. To our knowledge, we report for the first time the clinicopathological features and management options of an orbital CMF arising from the frontal bone.
A 37-year-old woman had slowly progressive swelling of the left upper eyelid temporally associated with occasional headache and shooting pain for 3 years. On examination, visual acuity was 20/20 OU. The left eye showed 4 mm of proptosis with downward displacement, mild blepharoptosis, and choroidal folds at the posterior pole (Figure 1A). Computed tomography disclosed a superotemporal, noninfiltrative orbital mass with erosion of the adjacent frontal bone (Figure 1B and C). Differential diagnosis included lacrimal gland tumors, atypical dermoid cysts, and benign fibro-osseous lesions such as osteoma, fibrous dysplasia, or ossifying fibromyxoid tumor of soft parts.