Intraocular Tumors

CHOROIDAL HEMANGIOMA

Choroidal hemangiomas are benign vascular tumors with no malignant potential. Circumscribed choroidal hemangiomas are usually isolated lesions, whereas diffuse hemangiomas are most often found in patients with Sturge-Weber syndrome. (See “Phakomatoses: SturgeWeber Syndrome” later in this chapter.) Circumscribed hemangiomas can usually be distinguished from melanomas and metastatic lesions on the basis of

their clinical appearance, angiographic features, and ultrasonographic characteristics.

Symptoms

Patients with circumscribed choroidal hemangiomas may be asymptomatic or report reduced visual acuity, visual field defect, metamorphopsia, or photopsias due to leakage of subretinal fluid into the macula. Occasionally, a large exudative retinal detachment can cause profound loss of vision.

Clinical Features

Choroidal hemangiomas are usually moderately elevated, dome shaped, and orange (often difficult to distinguish from the surrounding choroid). They often have pigment clumping or fibrous retinal pigment epithelial metaplasia over the surface. Subretinal fluid is often found overlying the tumor, tracking into the macula, or, less commonly, producing a large exudative retinal detachment. Diffuse choroidal hemangiomas may be seen in patients with Sturge-Weber syndrome. The fundus is described as having a “tomato catsup” appearance. The lesions may be difficult to identify with ophthalmoscopy unless the choroidal color is compared to the other, uninvolved eye.

Ancillary Testing

Ultrasonography is extremely useful in distinguishing choroidal hemangiomas from melanomas and metastatic lesions. On A-scan ultrasonography, hemangiomas typically demonstrate high internal reflectivity with relatively regular spikes. Fluorescein angiography is helpful but not diagnostic, and classically shows lobular early filling with late diffuse staining. Indocyanine green angiography may reveal a distinctive pattern of late hypofluorescence with “washout” of the dye.

Pathology/Pathogenesis

These tumors appear histopathologically as cavernous hemangiomas that replace the normal choroid. Most circumscribed choroidal hemangiomas arise spontaneously with no hereditary pattern or other systemic associations. The pathogenesis is unknown.

Treatment/Prognosis

Since choroidal hemangiomas are benign, they are usually observed without treatment unless they are affecting vision. Depending on the degree of subretinal fluid, treatment can include laser photocoagulation, transpupillary thermotherapy, photodynamic therapy, plaque radiotherapy, or external beam radiation. Patients may suffer visual loss in spite of successful control of associated subretinal fluid.

Systemic Evaluation

Circumscribed choroidal hemangiomas are usually isolated lesions and do not require systemic evaluation. Diffuse choroidal hemangiomas may be associated with Sturge-Weber syndrome.

Fundus photograph of a choroidal hemangioma occupying most of the temporal macula. Note that the tumor color is virtually indistinguishable from the surrounding choroid.

Late-phase fluorescein angiogram of a juxtapapillary choroidal hemangioma, demonstrating a diffuse, lobular pattern of hyperfluorescence.

Choroidal hemangioma with extensive fibrous metaplasia over the surface and surrounding pigmentary alterations consistent with a long-standing choroidal hemangioma.

Subtle choroidal hemangioma is difficult to distinguish from the surrounding choroid except for an area of gray fibrous metaplasia in the lower left region of the tumor.

B-scan ultrasonography of a choroidal hemangioma demonstrates a bright dome-shaped lesion with no choroidal excavation.

A-scan ultrasonography of a choroidal hemangioma demonstrates medium to high internal reflectivity and relatively uniform spikes.

CHOROIDAL MELANOMA

Choroidal melanoma is the most common primary intraocular cancer. The incidence in the United States is about five to eight cases per million per year. Risk factors include light skin pigmentation, blue irides, and increasing age. Although choroidal melanoma can be diagnosed at any age, most patients are in their sixth or seventh decade at diagnosis.

Symptoms

Patients may be asymptomatic or they may experience metamorphopsia, photopsia, peripheral field changes, floaters, or decreased visual acuity from direct obstruction of the visual axis, exudative retinal detachment, or vitreous hemorrhage. Pain is not a typical symptom except in neglected cases.

Clinical Features

Most melanomas are pigmented, although 20% to 30% are amelanotic. Most are dome shaped or mushroom shaped (indicating a rupture through Bruch’s membrane). Melanomas are thicker than nevi, ranging from around 2 mm to more than 15 mm in thickness. Findings may include orange lipofuscin pigment over the tumor surface, exudative retinal detachment, and subretinal or vitreous hemorrhage in larger tumors. Ciliary body melanomas can be associated with sentinel episcleral vessels, extrascleral extension, and induced lenticular astigmatism.

Ancillary Testing

Ultrasonography is the most important ancillary test. Choroidal melanomas typically display low to medium internal reflectivity on A-scan, which distinguishes them from metastatic deposits, hemangiomas, and other simulating lesions. Fluorescein angiography classically demonstrates intrinsic tumor vessels or the “double circulation,” and it can help to rule out a hemorrhagic process that would block fluorescence. Magnetic resonance imaging typically shows hyperintensity

on T1 weighting.

Pathology/Pathogenesis

The modified Callander system is usually used to classify choroidal melanomas into spindle, mixed, and epithelioid cell types, in order of worsening prognosis. Unlike cutaneous melanoma, no strong link exists between choroidal melanoma and sunlight exposure, and the vast majority of these tumors are sporadic, with no familial pattern.

Treatment/Prognosis

Treatment options include observation, transpupillary thermotherapy, plaque radiotherapy, charged particle therapy, stereotactic radiotherapy, local resection, or enucleation, depending on the size and location of the tumor, the overall health of the patient, and other factors. The Collaborative Ocular Melanoma Study demonstrated that the mortality rates following iodine 125 brachytherapy did not differ from mortality rates following enucleation for up to 12 years after treatment. Clinical risk factors for metastasis include larger tumors, anterior location, and greater age.

Systemic Evaluation

A metastatic workup should be performed before treatment. Choroidal melanoma has a propensity to metastasize to the liver and less commonly to the lung and other sites. A metastatic evaluation should minimally include liver function studies, chest x-ray, and physical examination. Abnormalities should be followed up with further imaging studies.

Slit lamp photograph demonstrates large temporal ciliochoroidal melanoma blocking the red reflex of the fundus.

Amelanotic choroidal melanoma with prominent intrinsic vessels.

Fundus photograph of a choroidal melanoma. The elevated, pigmented tumor had orange lipofuscin pigment over the tumor surface and subretinal fluid consistent with a choroidal melanoma.

Fluorescein angiogram of the same lesion in the previous figure shows irregular, intrinsic tumor vessels, the so-called double circulation, which can be distinguished from the overlying retinal vessels.

B-scan ultrasonography of a choroidal melanoma, demonstrating choroidal excavation and the classic mushroom shape that is seen in some tumors due to a break through Bruch’s membrane.

A-scan ultrasonography of a choroidal melanoma, demonstrating low to medium internal reflectivity and a tendency for spike height to decrease from left to right.