Intraocular Tumors
Evelyn X. Fu, MD, Brandy C. Hayden, BS, Arun D. Singh, MD*
KEYWORDS
Retinoblastoma Choroidal melanoma
Choroidal hemangioma Choroidal metastasis
Astrocytic hamartoma Choroidal osteoma
Ultrasonography is a powerful noninvasive tool for the accurate diagnosis and effective management of intraocular tumors. Distinguishing ultrasonographic characteristics of intraocular tumors result from their different histopathologic compositions that can be evaluated with one-dimensional reflectivity analysis (A-scan) and two-dimensional acoustic section (B-scan). Information regarding location, shape, and acoustic characteristics is considered together to aid the diagnosis of intraocular tumors. Determination of size progression and extension is critical in selecting and monitoring management.
RETINOBLASTOMA
Retinoblastoma is an important differential diagnosis in children presenting with leukocoria. The clinical presentation of retinoblastoma varies with the stage of the disease at the time of recognition. In its earliest clinical stage, retinoblastoma presents as a flat transparent to slightly white lesion in the sensory retina. As the tumor enlarges, it loses its transparency and becomes creamy yel- low-white with foci of chalk-like calcification. As these tumors leave the confines of the retina with continued growth, they assume either an endophytic or exophytic pattern. Endophytic retinoblastomas grow from the retina inward toward the vitreous cavity. Seeding from these friable tumors in the vitreous and anterior chamber can simulate endophthalmitis and other inflammatory conditions. Exophytic retinoblastomas grow from the retina outward into the subretinal space and can cause exudative retinal detachment, sometimes displacing the retina anteriorly behind the lens. Advanced retinoblastoma can present with
neovascular glaucoma with corneal edema, spontaneous hyphema, vitreous hemorrhage, pseudohypopyon, and vitritis.
Ultrasonography is very valuable in detecting retinoblastoma and differentiating it from other causes of leukocoria, particularly when funduscopic examination is limited in advanced cases. The internal reflectivity of these lesions varies according to the degree of calcification within the lesion. Noncalcified tumors show low-to-medium reflectivity, whereas calcified lesions exhibit high reflectivity (Fig. 1). With significant calcification, shadowing of the adjacent sclera and orbit occurs. B-scan typically displays a rounded or irregular intraocular mass. Mildly elevated diffuse lesions, however, have been reported.1,2 Depending on the clinical presentation, associated ultrasonographic findings may include retinal detachment and vitreal opacities (Fig. 2).
Retinoblastoma has a predilection to invade the optic nerve and extend extraocularly. Optic nerve involvement and extraocular extension can be difficult to detect with ultrasound because of shadowing in cases with extensive calcification. CT and MR imaging should be used when optic nerve or extraocular invasion is suspected.
DIFFERENTIAL DIAGNOSIS OF RETINOBLASTOMA
Numerous childhood ocular conditions can cause leukocoria and therefore simulate retinoblastoma. The conditions that most commonly present a diagnostic challenge include retinopathy of prematurity (ROP), persistent hyperplastic primary vitreous (PHPV), Coats’ disease, toxocariasis, and medulloepithelioma (Table 1).
Department of Ophthalmic Oncology, Cole Eye Institute (i-32), 9500 Euclid Avenue, Cleveland Clinic, Cleveland, OH 44195, USA
* Corresponding author.
E-mail address: singha@ccf.org (A.D. Singh).
Ultrasound Clin 3 (2008) 229–244 doi:10.1016/j.cult.2008.04.002
1556-858X/08/$ – see front matter ª 2008 Elsevier Inc. All rights reserved.
ultrasound.theclinics.com
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Fu et al |
Fig.1. Retinoblastoma with calcification. Fundus photograph (A). Transverse B-scans demonstrate a large, domeshaped lesion with marked internal calcification. High gain showing the lesional boundaries (B, arrows). Low gain showing internal calcification causing shadowing of the orbit (C, arrow).
Retinopathy of Prematurity
ROP is usually bilateral, with most patients having some degree of short axial length. In severe cases, the retina is dragged toward the fibrovascular lesion in the periphery, producing leukocoria. In
the most advanced cases, the retina is detached in a funnel-like configuration, resulting in a hyperreflective retrolental membrane on the B-scan. The peripheral retina frequently exhibits a loop or trough-like appearance as a result of traction by the retrolental membrane (Fig. 3).
Fig. 2. Retinoblastoma with associated retinal detachment. Fundus photograph (A). Longitudinal B-scan demonstrates a large, dome-shaped lesion with internal calcification (back arrow) and retinal detachment (white arrow) over the apex of the lesion and extending peripherally (B).
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Intraocular Tumors |
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Table 1 |
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Differential diagnosis of retinoblastoma |
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Condition |
Presentation |
Laterality |
Axial Length |
USG Characteristics |
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Retinoblastoma |
Few months to <2 years; |
Unilateral |
Normal |
Intraretinal/subretinal |
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possible family history |
Bilateral |
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mass with calcification |
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ROP |
Days to few months |
Bilateral |
Short |
RD with retinal loops |
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after birth; |
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prematurity; oxygen |
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supplementation |
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PHPV |
Days to weeks |
Unilateral |
Short |
Vitreous band from |
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after birth |
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lens to optic nerve |
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Coats’ disease |
4–10 years; most |
Unilateral |
Normal |
Exudative RD |
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commonly males |
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Subretinal hyper- |
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reflective particles |
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Toxocariasis |
Contact with dogs |
Unilateral |
Normal |
Peripheral mass, |
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vitreoretinal band, |
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traction RD |
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Medulloepithelioma |
First decade of life |
Unilateral |
Normal |
Ciliary body mass |
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with cyst |
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Abbreviations: PHPV, persistent hyperplastic primary vitreous; RD, retinal detachment; ROP, retinopathy of prematurity; USG, Ultrasonography.
Persistent Hyperplastic Primary Vitreous
PHPV is a congenital condition that usually presents during the first few days or weeks of life. In contrast, retinoblastoma typically presents months after birth. In most cases, PHPV is a unilateral condition in a micro-ophthalmic eye. On B-scan, the lens is often thin, and the posterior capsule is irregular (Fig. 4). A retrolental membrane on the posterior surface of the lens with a vitreal band extending from this membrane to the optic disc is characteristic. The vitreal band
Fig. 3. Retinopathy of prematurity. Longitudinal B-scan demonstrates a highly reflective, closed fun- nel-shaped retinal detachment (arrows) inserting into the disc.
may be extremely thin, and its entire course may not be visualized. Some vitreal bands can be extremely thick and can simulate a tightly closed, funnel-shaped retinal detachment (see Fig. 4).
Coats’ Disease
Coats’ disease is a unilateral retinal vascular disorder characterized by telangiectasia, intraretinal exudation, and exudative retinal detachment. Although Coats’ disease can present at any age, it usually is diagnosed in young males between 4 and 10 years of age.3 Retinoblastoma, however, has no sex predilection and typically is diagnosed before 2 years of age. In early stages of Coats’ disease, localized, shallow retinal detachments may occur (Fig. 5). Eyes with more advanced disease, however, present with total exudative detachments as a result of leakage from the aneurysmal blood vessels. Cholesterol crystals left in the subretinal space from the exudation are observed clinically as refractile particles. These particles are much less reflective than the calcium particles in retinoblastoma. Ultrasonography is valuable by demonstrating a tumor beneath the retinal detachment in retinoblastoma, whereas no distinct tumor can be shown in Coats’ disease.4
Toxocariasis
Toxocariasis is caused by infestation of the eye with Toxocara canis. Ocular toxocariasis may