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Show J. Clin. Neuro-ophthalmol. 4: 49-52, 1984. Aneurysmal Bone Cyst of the Orbit A Case Report GARRON L. KLEPACH, M.D. ROBERT E. M. HO, M.D. JOHN K. KELLY, D.O. Abstract We report a case of orbital aneurysmal bone cyst, a rare orbit tumor with unusual clinical features. Introduction Aneurysmal bone cyst is an uncommon bone tumor occurring rarely in the orbit.! We are reporting this case of aneurysmal bone cyst because of its rarity in the orbit and the unusual clinical features. Case Report A 35-year-old healthy woman developed painless blurred vision in the right eye 6 weeks prior to admission. Her only previous visual problem was myopia for which she used corrective lenses prescribed 2 years earlier. She measured 20/20 in both eyes with -3.75 - 1.50 x 170 in the right eye and -4.50 - 1.50 x 175 in the left eye. Five weeks prior to admission, a new refraction revealed anisometropia which was not present 2 years earlier, but correctable to 20/20 in both eyes. She then measured -1.00 - 1.00 x 170 in the right eye and -4.75 - 1.50 x 175 in the left eye. One week later, blurring returned in the right eye now associated with right periorbital and adnexal puffiness. Repeat refraction again corrected her vision to 20/20 in the right eye, but myopia had decreased in the right eye to -0.50 -1.00 x 175, while the left eye remained the same. Plain x-ray films of the skull and laminograms of the orbit were reported with no bony abnormality. From the Neuro-ophthalmo!ogy Section, Kresge Eye Institute (GLK), Neuro-Surgery Department (REMH), and Neuro-Radiology Section (JKK), Wayne State University School of Medicine, Detroit, Michigan. March 1984 Four weeks prior to admission, she developed a throbbing ache behind the right eye, intermittent diplopia that eventually became constant, and increasingly obvious proptosis. At no time did she have any other neurologic symptoms. The patient was a healthy 35-year-old woman in no distress. A general medical examination was completely normal. Neurologic examination revealed only anosmia of the right nostril. Ophthalmologic examination on admission showed a visual acuity of 20/20 in both eyes with a refractive error of -0.50 -1.25 x 180 (right eye) unchanged from 1 month ago. The left eye always remained the same. Pupil examination was normal with light and near responses showing no afferent defect. Ocular motility showed limited ductions in the right eye only. There was 85% limitation of elevation and 25% limitation of both adduction and abduction. Goldmann perimetry showed an irregular superotemporal monocular defect with a 1/4 mm2 target in the right eye. The left eye showed a nasal inferior defect with a small isopter that was not thought clinically significant. Dilated ophthalmoscopy showed distortion of the right peripapillary and macular area with retinal stria. Slit lamp and applanation tension examination were normal. Examination of the orbit and adenexa showed no palpable mass nor tenderness. However, there was a marked decrease in orbital resilience in the right eye. Exophthalmometry revealed a 3-mm right proptosis displaced slightly downward. There was no ptosis. Radiographic Studies Review of outside plain skull and orbit films and cerebral angiography showed no bony abnormality and an avascular orbital mass. A highresolution computerized axial tomography (CT scan) revealed a large mildly enhancing right orbital apex mass located superonasaUy and extending forward through the middle third of the 49 Aneurysmal Bone Cyst (a) (b) Figures la and lb. CT scan of aneurysmal bone cyst. (a) Coronal section showing elevation and distortion of the orbit roof. (b) Horizontal section showing loculated cystic mass. orbit. On the CT scan, the mass could not be entirely separated from the superior rectus muscle. The mass was cystic in appearance and had eroded the orbit roof with no penetration nor extension intracranially (Fig. 1). Orbital venography showed major displacement of the vessels medially and inferiorly. Surgery An initial attempt to remove the tumor through a lateral orbitotomy approach was not successful because of the medial location and bulky appearance of the tumor in the orbit. It was suspected at surgery that this was a vascular tumor. Journal of Clinical Neuro-ophthalmology Klepach, Ho, Kelly -- - --, ' .. ~.". . .... ~ ... - .... : Ii - -.- ....' ~ .... -. .... . ~ " ... - • ~. ,.to ~ _:.t.:.- ..,."... . ..--' .. .-.. Figure 2. Photomicrograph (x80) of aneurysmal bone cyst, showing a pseudovascular or cystic space surrounded by blood-filled channels, with multinucleated giant cells and islands of bone, One week later, she was returned to the operating room where she underwent a frontal craniotomy and unroofing of the right orbit while preserving the optic canal. The operative findings included an encapsulated, rubbery multiloculated tumor containing a large amount of serosanguinous fluid, brownish in color and sterile. The tumor capsule was easily separated from orbital periosteum and muscle cone. While the muscle cone and globe were compressed, there was no adhesion infiltration or extension into these structures. The tumor was removed entirely. Her surgical postoperative course was uneventful. Pathology Pathologic examination of the tumor showed bone and connective tissue fragments of osteoid and new bone formation, foci of old hemorrhage, cellular stroma containing multinucleated giant cells, and channels lined by endothelial cells containing blood. No epithelial lining or underlying malignancy was identified (Fig. 2). Postoperative Course Ophthalmologic findings immediately postoperatively included the same vision, refractive er-ror, ocular motility, and proptosis findings as preoperative. Within 3 weeks, ocular motility limitation had improved substantially. At 3 months there was full ocular motility with no diplopia, no proptosis, and normal ophthalmoscopy. The only persistent ocular finding was anisometropia that while not improving, had changed the cylinder astigmatic component to -1.50 -1.00 X 95, 20/20 (right eye). Discussion The age of this patient is 35 years, substantially older than expected for aneurysmal bone cyst. When occurring elsewhere in the bony skeleton, 80% of the aneurysmal bone cyst cases are under the age of 20 years. 2 Her age and rapid development of clinical findings made the differential diagnosis difficult. Rhabdomyosarcoma in this age group is unusual. Neurofibroma, meningioma, epidermoid, or dermoid would unlikely progress with such rapid course. Lymphoid tumors do not have cystic features on CT scan and there was no medical support for suspecting this. Hemangioma and hemangioblastoma are frequent orbit tumors. Hadders and Oterdoom3 suggested aneurysmal bone cyst is an hemangioma, while others do not agree.4,5 Lichtenstein, who first described this tumor in 1942, suggested March 1984 51 Aneurysmal Bone Cyst aneurysmal bone cyst tumors arise from intraosseous arteriovenous shunts with increased venous pressure and a dilated engorged vascular bed within the bone.6 By appearing cystic, this case differed on the CT scan from our other cases of orbit hemangioma and did not show the unusual angiographic features reported with orbital aneurysmal bone cyst.? The working diagnosis for orbitotomy was mucocoele. Aneurysmal bone cyst was not suspected. With pathologic examination of the totally removed tumor, there was no telangiectatic osteosarcoma, osteogenic sarcoma, or giant cell tumor masquerading as aneurysmal bone cyst. The patient's initial complaint was blurred vision, and documented refraction was a 3.25-diopter reversal in her myopic correction over a short 2-week period. Indentation of the posterior pole by a rapidly expanding posterior orbit mass would shorten the axial length of the globe and reduce the required myopic correction. Vision and refractive changes preceded diplopia and proptosis, and improved least postoperatively. A-scan ultrasound was not performed, but might have shown the suggested axial length asymmetry and given more pathological clue. The operative finding of loculated serosanguinous cysts correlates with both CT scan appearance and the rapid clinical presentation and progression. A calvarium aneurysmal bone cyst in an elderly man with unremarkable skull films was reported by Keuskamp et al.,s because the aneurysmal bone cyst extended intracranially and spontaneously hemorrhaged into the temporal lobe. Similarly, this aneurysmal bone cyst represents a hemorrhagic "blowout" extension into the orbit with exclusively ophthalmologic signs rather than intracranial extension producing coma or neurologic symptoms. CT scan findings of cystic mass emanating from and distorting the sphenoid or elsewhere within the bony orbit may be characteristic for aneurysmal bone cyst (Fig. 1). Conclusion The course of this reported case suggests aneurysmal bone cyst of the skull and orbit can present in two clinical forms. The more common evolution is a slow-growing tumor. When the aneurysmal bone cyst suddenly expands, a hemorrhagic blowout of the distorted bone can produce a rapid progression of ophthalmologic and orbit findings or sudden neurologic failure as reported previously. 8 References 1. Ronner, H.J., and Jones, 1.5.: Aneurysmal bone cyst of the orbit: A review. Ann. Ophthalmol. 15: 626-629, 1983. 2. Dahlin, D.C.: Bone Tumors (3rd ed.). Charles C Thomas, Springfield, 1978, p. 370. 3. Hadders, H.N., and Oterdoom, H.J.: The identification of aneurysmal bone cyst with hemangioma of the skeleton. J. Pathol. Bacteriol. 71: 193-200, 1956. 4. Spjut, H,J., Dorfman, H.D., Fechner, RE., and Ackerman, L.V.: Atlas of Tumor Pathology: Tumors of Bone and Cartilage. Armed Forces Institute of Pathology, Washington, D.C., 1971, p. 361. 5. Tillman, B.P., Dahlin, D.C., Lipscomb, P.R., and Stewart, J,R: Aneurysmal bone cyst: Analysis of ninety-five cases. Mayo Clin. Proc. 43: 478-495, 1968. 6. Lichtenstein, L.: Bone Tumors (5th ed.). C.V. Mosby, St. Louis, 1977, p. 419. 7. O'Gorman, A.M., and Kirkham, T.H.: Aneurysmal bone cyst of the orbit with unusual angiographic features. Am. J. Roentgenol. Radium. Ther. Nucl. Med. 126: 896-899, 1976. 8. Keuskamp, P.A., Horoupian, D.S. and Fein, J.M.: Ane~rysmal bone cyst of the temporal bone presenting as a spontaneous intracerebral hemorrhage. Neurosurgery 7: 166-170, 1980. Acknowledgments The authors thank Dr. John Crissman for his histopathologic opinion and photographic assistance. Write for reprints to: Garron L. Klepach, M.D., 3994 John R., Detroit, Michigan 48201. Journal of Clinical Neuro-ophthalmology |
