Choroidal Melanocytic Lesions

TODAY’S PRACTICE CLINICAL PEARLS

Choroidal and Retinal Tumors in Adults: Choroidal Melanocytic Lesions

Part two of a four-part series on guidelines for diagnosing and treating ocular lesions.

BY TERESA DIAGO, MD; LUIS AMSELEM, MD; AND JOSE S. PULIDO, MD, MPH, MS, MBA

n the first article of this series (Choroidal and Retinal Tumors in Adults: Vascular Tumors of the Retina, June 2011, page 76), we discussed vascular tumors of the retina. In this second article, we describe the clinical features,I diagnosis, and treatment of three types of choroidal melanocytic lesions.

CHOROIDAL NEVUS Choroidal nevus (Figure 1), the most common primary intraocular tumor,1 is a benign tumor that arises from melanocytic cells derived from the neural crest. Choroidal nevi are more common in white people, with 4% of the population having at least one.1 Malignant transformation into melanoma is possible; therefore, choroidal nevi should be monitored even though the rate is 1 in 4,000.2 As noted below, certain risk factors are associated with a higher risk of transformation. Clinical features. Most choroidal nevi are congenital, but they usually do not become pigmented and Figure 1. Choroidal nevus. clinically detectable until after childhood. They can be pigmented, amelanotic, or partially pigmented. ments and to determine acoustic hollowness, a prog- Although the majority of choroidal nevi are asympto- nostic factor that is associated with the nevus possibly matic, approximately 11%, either subfoveal or located being malignant. near the fovea, become symptomatic later due to sub- Differential diagnoses. The differential diagnoses of retinal fluid and choroidal neovascularization.3 choroidal nevus include choroidal melanoma, metastat- Diagnostic approaches. There is little difference in ic carcinoma, choroidal hemangioma, choroidal osteo- the diagnostic and prognostic values of fluorescein ma, schwannoma, subretinal or suprachoroidal angiography (FA) or indocyanine green (ICG) angiogra- hematoma, congenital hypertrophy of the retinal pig- phy. Choroidal nevi can vary from hypo- to hyperfluo- ment epithelial (RPE) cells, and reactive hyperplasia of rescence. Most benign choroidal nevi do not have the RPE. prominent intralesional blood vessels, whereas most Management. Asymptomatic choroidal nevus does choroidal melanomas do. Fundus autofluorescence not require treatment. In symptomatic cases with (FAF) is useful because it detects orange pigment, one choroidal neovascularization or subretinal fluid, laser of the most relevant risk factors for a growing tumor.4 photocoagulation, photodynamic therapy, or Ultrasound can be used for baseline thickness measure- transpupillary thermotherapy can be used; however,

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Posterior uveal melanoma is the most common primary malignant intraocular neoplasm in adults.

these cases should be referred to a specialist because they are often symptomatic due to malignant transformation.5 All lesions should be monitored for early detection of malignant transformation. Clinical factors that are statistically predictive of growth of choroidal melanocytic tumors include thickness greater than 2 mm, subretinal fluid, presence of symptoms, orange pigment, tumor margin within 3 mm of the disc, hollowness on ultrasonography, lack of halo, and lack of drusen.5-8 Patients with choroidal nevi showing no risk Figure 2. Choroidal melanoma. factors should initially be examined every 12 months. Those with one or two risk factors should be monitored uation must be done once or twice a year, as malignant every 4 to 6 months. Patients with three or more risk fac- transformation into a melanoma is rare but possible.11 tors should be evaluated at a reputable center for management alternatives and possible treatment because of POSTERIOR UVEAL MELANOMA the high risk of ultimate malignant transformation.6 Posterior uveal melanoma is the most common primary malignant intraocular neoplasm in adults.12 It aris- MELANOCYTOMA es from melanocytes in the posterior uveal tract. These Melanocytoma is an unusual congenital and non- lesions can be pigmented, amelanotic, or partially pig- hereditary variant of melanocytic nevus that is classically mented. It is believed that uveal melanomas can arise located on the optic disc.9 Usually there is a surround- from preexisting nevi. Early detection and treatment of ing peripapillary choroidal nevus. Melanocytoma can uveal melanoma when the malignancy is small may also be located in the iris, ciliary body, or choroid. It is reduce the risk for metastasis and increase survival.13 usually composed entirely of maximally pigmented, Many of these tumors arise from mutations in the polyhedral nevus cells. Melanocytoma is, by definition, GNAQ pathway. This is different from skin melanomas, never amelanotic. many of which arise from mutations in the BRAF path- Clinical features. The mean age at diagnosis is 50 years, way. Additionally, there are two forms of uveal and melanocytoma does not appear to have a predilec- melanoma, one which has monosomy 3 by fluorescence tion for lightly pigmented races.10 Melanocytoma is in situ hybridization (FISH) analysis and class 2 by almost always unilateral and appears as a dark brown to mRNA analysis, and another which has disomy 3 by black lesion, affecting the optic disc and the peripapillary FISH and class 1 by mRNA analysis. Monosomy 3 class 2 area. Optic disc melanocytomas have feathery edges that melanomas have a high probability of developing extend along the nerve fiber layers. Malignant transfor- metastases, and disomy 3 class 1 melanomas have a mation is uncommon. Ocular melanocytosis can be seen very low tendency to metastasize. The more malignant in patients with melanocytoma, especially in more pig- class 2 type is associated with braca associated protein- mented individuals. But melanoma is also more common 1 mutations. in persons with melanocytosis, so careful evaluation by Clinical features. Clinically, class 1 and class 2 appear an expert is indicated. the same; class 2 lesions tend to be thicker and more Diagnostic approaches. FA typically shows hypofluo- anterior in location, but only biopsy can distinguish the rescence of the lesion, but it is not very useful for differ- two types.14 Ciliary body melanoma is usually a dome- entiating melanocytoma from melanoma. shaped mass associated with external signs such as sen- Differential diagnoses. Uveal nevi and melanomas tinel vessels or an epibulbar pigmented lesion, which is are the main differential diagnoses. a sign of extrascleral extension.15 Erosion into the anteri- Management. Fundus photography and clinical eval- or chamber via the iris root can be seen by gonioscopy

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lary thermotherapy, charged particle radiation, plaque TAKE-HOME MESSAGE brachytherapy, other radiation methods such as stereo- • Choroidal nevus is a benign tumor that can transform into tactic radiosurgery, gamma-knife and cyberknife meth- melanoma. Choroidal nevi, either subfoveal or located near ods, local resection, enucleation, orbital exenteration, 17 the fovea, may become symptomatic due to subretinal fluid and combinations of these options. Plaque brachyther- and choroidal neovascularization. apy is the most commonly used option. An ocular oncol- ogist should decide what procedure should be done. • Melanocytoma is classically located on the optic disc but can also be found in the iris, ciliary body, or choroid. CONCLUSION • Posterior uveal melanoma arises from melanocytes in the Subsequent installments in this series will examine posterior uveal tract. choroidal metastases, intraocular lymphomas, vascular tumors of the choroid, and other tumors. ■ and in advanced cases by direct slit-lamp examination. Ciliary body melanoma can also be diffuse, presenting Luis Amselem, MD, is a Consultant in the Department of as a ring melanoma with raised intraocular pressure Ophthalmology at the Hospital Moises Broggi, Barcelona, (IOP). Thus, ciliary body melanoma must be ruled out Spain. Dr. Amselem states that he has no financial interest in the presence of iris heterochromia and unilateral in the material presented in this article. He may be reached raised IOP in heavily pigmented eyes. Choroidal at e-mail: [email protected]. melanoma (Figure 2) usually presents as a solitary, Teresa Diago, MD, is a Consultant in the Department of dome-shaped or sessile tumor, although multicentric Ophthalmology at the Hospital de Sagunto, Valencia, lesions can occur. Prominent clumps of orange pigment Spain. Dr. Diago states that she has no financial interest in are frequently present. Exudative retinal detachment the material presented in this article. She may be reached and tumor-associated retinal pigment epitheliopathy at e-mail: [email protected]. can lead to vision loss.16 Jose S. Pulido, MD, MPH, MS, MBA, is a Professor in the Diagnostic approaches. Ultrasound A- and B-scans Department of Ophthalmology at the Mayo Clinic, usually reveal a solid dark mass with low internal reflec- Rochester, Minnesota. Dr. Pulido states that he has no tivity and characteristic hollowness. FA and ICG usually financial interest in the material presented in this article. reveal prominent intralesional blood vessels. FAF is use- He may be reached at e-mail: [email protected]. ful to highlight the presence of lipofuscin. Computed tomography (CT) and magnetic resonance imaging 1.Gass JDM.Choroidal nevi or benign melanomas.In:Gass JDM,ed.Differential Diagnosis of Intraocular Tumors.A Stereoscopic Presentation.St.Louis:Mosby;1974:14. (MRI) are occasionally used to image uveal melanomas, 2.Shields CL,Furuta M,Berman EL,et al.Choroidal nevus transformation into melanoma.Analysis of 2514 consecu- although the technology is not specific or sensitive. CT tive cases.Arch Ophthalmol.2009;127(8):981-987. 3.Gonder JR,Augsburguer JJ,McCarthy EF,Shields JA.Visual loss associated with choroidal nevi.Ophthalmology. shows pronounced contrast enhancement, and MRI 1982;89(8):961-965. shows a mass hyperintense in T1 and hypointense in T2. 4.Gunduz K,Pulido JS,Bakri SJ,Amselem L,Petit-Fond E,Link T.Fundus autofluorescence of choroidal melanocytic lesions and the effect of treatment.Trans Am Ophthalmol Soc.2007;105:172-179. When positron emission tomography (PET) is done to 5.Shields JA,Shields CL.Choroidal nevus.In:Shields JA,Shields CL,eds.Intraocular Tumors.A Text and Atlas. determine the presence of clinical metastases, the pri- Philadelphia:WB Saunders;1992:85-100. mary medium and large uveal melanomas can some- 6.Shields CL,Shields JA,Kiratli H,De Potter P,Cater JR.Risk factors for growth and metastasis of small choroidal melanocytic lesions.Ophthalmology.1995;102(9):1351-1361. times be fluorodeoxyglucose (FDG) avid as well. Early 7.Shields CL,Cater JC,Shields JA,Singh AD,Santos MC,Carvalho C.Combination of clinical factors predictive of detection of choroidal melanoma is crucial. The risk fac- growth of small choroidal melanocytic tumors.Arch Ophthalmol.2000;118(3):360-364. 8.Collaborative Ocular Melanoma Study Group.Factors predictive of growth and treatment of small choroidal tors for growth and metastases are discussed in the melanoma:COMS report No.5.Arch Ophthalmol.1997;115(12):1537-1544. nevus section above. 9.Reidy JJ,Apple DJ,Steinmetz RL,et al.Melanocytoma:nomenclature,pathogenesis,natural history and treatment. Surv Ophthalmol. 1985;29(5):319-327. Differential diagnoses. Differential diagnoses of uveal 10.Shields JA,Demirci H,Mashayekhi A,Shields CL.Melanocytoma of optic disc in 115 cases:the 2004 Samuel melanomas includes choroidal nevus, metastatic carcino- Johnson Memorial Lecture,part 1.Ophthalmology.2004;111(9):1739-1746. ma to the choroid, choroidal lymphoma, exudative age- 11.Shields JA,Demirci H,Mashayekhi A,Eagle RC Jr,Shields CL.Melanocytoma of the optic disk:a review.Surv Ophthalmol.2006;51(2):93-104. related macular degeneration, subretinal or suprachoroidal 12.Seddon JM,Young TA.Epidemiology of uveal melanoma.In:Ryan SJ,Hinton DR,Schachat AP,eds.Retina,4th ed.St. hematoma, choroidal hemangioma, posterior nodular scle- Louis:Elsevier Mosby;2006:692-697. 13.Shields CL,Furuta M,Thangappan A,et al.Metastasis of uveal melanoma millimeter-by-millimeter in 8033 con- ritis, choroidal osteoma, bilateral diffuse uveal melanocytic secutive eyes.Arch Ophthalmol.2009;127(8):989-998. proliferation, congenital hypertrophy of the RPE, reactive 14.Shields CL,Gaunguly A,Bianciotto CG,Turaka K,Tayallali A,Shields JA.Prognosis of uveal melanoma in 500 cases using genetic testing of fine-needle aspiration biopsy specimens.Ophthalmology.2011;118(2):396-401. hyperplasia of the RPE, and ocular melanocytosis. 15.Shields JA,Shields CL.Clinical features of posterior uveal melanoma.In:Shields JA,Shields CL,eds. Intraocular Management. Several treatment options are available tumors:A Text and Atlas.Philadelphia:WB Saunders;1992:85-100. 16.Damato BE,Foulds WS.Tumour-associated retinal pigment epitheliopathy.Eye (Lond).1990;4(Pt 2):382-387. for the management of uveal melanomas, depending on 17.Shields CL,Shields JA.Recent developments in the management of choroidal melanoma.Curr Opin Ophthalmol. the size and location of the tumor, including transpupil- 2004;15(3):244-251.

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