Diagnosis, Workup and Treatment
The patient’s presentation of proptosis and diplopia was in line with an orbital process, as confirmed with MRI. It is not uncommon for an intraconal mass to cause secondary globe compression resulting in the notable chorioretinal folds seen on fundoscopic assessment.  

Therefore, the next step was to obtain tissue for a definitive diagnosis. Fortunately, the MRI was very helpful in making a presumptive diagnosis of cavernous hemangioma, given its rather characteristic radiological findings. 
 
The patient underwent left orbitotomy with complete removal of a 30 mm x 26 mm x 19 mm circumscribed vascular mass (Figure 4). Microscopic pathology demonstrated an encapsulated tumor composed of endothelium-lined vascular channels separated by septae, with areas of smooth muscle as well as chronic inflammation (Figure 4). There was no evidence of malignancy. The features were consistent with a diagnosis of orbital cavernous hemangioma.

At three years’ follow-up, the patient has done well with visual acuity of 20/20 OD and 20/25 OS. Extraocular muscle surgery allowed for resolution of myogenic diplopia. Funduscopically, the left eye revealed persistent RPE changes with resolution of the chorioretinal folds.

Discussion
Orbital cavernous hemangioma is a benign, slowly progressive tumor that typically manifests as a unilateral mass, most often located within the muscle cone.^1-4 In 2004, Jerry Shields, MD and co-workers conducted a survey of 1,264 patients who were referred to their clinic for evaluation of space-occupying lesions, and found that orbital cavernous hemangioma was the third most commonly diagnosed orbital mass.¹ Orbital cavernous hemangioma accounted for 6 percent of the total cases and 36 percent of vasculogenic lesions.¹

Patients with orbital cavernous hemangiomas typically present with painless proptosis.^2-5 Other signs include globe compression with choroidal/chorioretinal folds, optic nerve compression with decreased vision, visual field changes, acquired hyperopia and diplopia.^1-5 The characteristic MRI findings of orbital cavernous hemangiomas include a well-defined mass that is hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging.^3,6-7 Contrast enhancement shows initial heterogeneous enhancement, which progresses to homogeneous enhancement.^3,6-7 One study of 214 cases of orbital cavernous hemangiomas found that imaging using echography and computed tomography or MRI could correctly diagnose 93 percent of cases prior to surgery.⁸

The differential diagnosis for a round, well-circumscribed, solid mass includes cavernous hemangioma, hemangioperictyoma, schwannoma, solitary fibrous tumor, neurofibroma and melanoma.² Other conditions to consider in the differential diagnosis include lymphoma, fibrous histiocytoma, lymphangioma, metastasis and inflammatory lesions.^1-6

Management of orbital cavernous hemangioma varies depending on the clinical presentation. Small, asymptomatic orbital cavernous hemangiomas can be monitored for progression.² Dr. Shields noted that only 52 percent of orbital cavernous hemangiomas necessitated surgical removal.¹ If surgical removal is indicated due to tumor size or symptoms, various techniques can be used depending on tumor location and size. The two main surgical approaches include the transconjunctival technique for tumors located anteriorly and the lateral orbitotomy for tumors in the mid and posterior orbit.² A transcranial approach and an endoscopic approach have been described for posterior tumors located near the orbital apex.²

Chorioretinal folds are relatively common in patients with orbital tumors. The patient in this case had unilateral oblique chorioretinal folds. These folds are seen as linear alterations at the level of the retina, retinal pigment epithelium and choroid, which represent undulations of the tissue, often causing shifting of the RPE.^9-12 Such folds generate a broad differential diagnosis, including hyperopia, hypotony, AMD, thyroid eye disease, scleritis, uveitis, orbital or choroidal tumor, post­op changes, uveal effusion syndrome and optic nerve head swelling.^9-13 One study noted that the rate of diagnosis of idiopathic chorioretinal folds has been decreasing, likely due to more accurate diagnostic tests.¹⁰

The laterality of the chorioretinal folds can provide a diagnostic clue to help narrow the diagnosis. Two recent studies found that 42 to 44 percent of chorioretinal folds were bilateral and that the rest were unilateral.^11,13 In one study, researchers compared 54 cases of bilateral and unilateral chorioretinal folds and found that, in addition to idiopathic, the most common causes of bilateral chorioretinal folds were AMD and hypotony, while unilateral cases were most commonly due to scleritis, ocular tumors, retinal vascular occlusion and hypotony.¹³ The characteristics and orientation of the chorioretinal folds can also provide useful information about the underlying cause. In this study, researchers described five unique orientations for chorioretinal folds: horizontal; oblique; vertical; radiating; and concentric.¹³ The horizontal orientation was noted in 70 to 77 percent of folds.¹³

Another report described the biomechanical forces that lead to chorioretinal folds in different etiologies, including orbital tumors.11 The author explained that intraconal orbital tumors lead to optic nerve displacement and cause the choroidal folds to originate from the nerve and radiate outwards.¹³ On the other hand, he found that extraconal tumors will lead to compression of the sclera and choroid, causing the folds.¹³ One notable finding was that an investigation of the pattern of the folds can help determine the tumor location.¹³

In conclusion, orbital cavernous hemangioma is a benign, slowly progressive vascular tumor that generally manifests in middle-aged patients. This mass can cause painless proptosis as well as compressive features such as chorioretinal folds accompanied by vision loss. Surgical removal of the tumor can resolve vision loss in some cases.  REVIEW

The author would like to thank Carol Shields, MD, and Sara Lally, MD, of the Wills Eye Ocular Oncology Service, and Ralph Eagle, MD, of Wills’ Ophthalmic Pathology Department for their assistance with this report.

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