CASE REPORTS IN OCULAR ONCOLOGY: Small Choroidal Melanoma With All Eight Risk Factors for Growth
Uveal melanoma prognosis is dependent on several factors including tumor size, location, configuration, extraocular extension, cell type, and cytogenetic abnormalities. In general, the smaller the tumor, the better the prognosis.1 In a recent publication on 8,033 eyes with uveal melanoma, it was documented that increasing thickness of uveal melanoma was associated with greater risk for metastasis and ultimate death.1 Patients with uveal melanoma measuring 2.5 mm thickness showed metastasis in 12% at 10 years as compared with 26% for those at 4.5 mm thickness.1 Hence, early detection of uveal melanoma is important.
The dilemma of early recognition centers on the difficulty in differentiating a benign choroidal nevus from a small malignant melanoma. Risk factors for identification of small melanoma, when it might resemble choroidal nevus, have been identified from several oncology centers. In an analysis of 2,514 patients with small choroidal melanocytic tumors, eight important parameters were found to be predictive of tumor growth; these include tumor Thickness of greater than 2 mm, subretinal Fluid, Symptoms of reduced vision or photopsia, Orange pigment, tumor Margin less than or equal to 3 mm from the optic disc, ultrasound Hollowness, absence of surrounding depigmented Halo and absence of overlying Drusen.2 These factors are remembered by the lettering TFSOM-UHHD representing the mnemonic “To Find Small Ocular Melanoma- Using Helpful Hints Daily.”2 Most patients with small melanoma display two or three of these factors.2 In this case presentation, we describe a small melanoma with all eight risk factors and discuss the importance of early detection of uveal melanoma.
A 55-year-old white woman noted photopsia for 1 year and slight blurred vision in the right eye. Her visual acuity was 20/30 in her right eye and 20/20 in the left eye. The anterior segment was unremarkable in both eyes. The left fundus was normal. In the right fundus, there was a small pigmented choroidal lesion located 2.5 mm from the optic nerve, measuring 7.5 x 5.5 mm in basal diameter and 2.3 mm in thickness without overlying drusen (Figure 1). The lesion manifested confluent overlying orange pigment, documented on autofluorescence, and subtle subretinal fluid, confirmed on optical coherence tomography (OCT). Ultrasonography demonstrated acoustic hollowness within the mass on B-scan and low to medium internal reflectivity on A-scan. The presence of all eight risk factors in this case was strongly suggestive of small choroidal melanoma rather than nevus. Despite the small size of the tumor, it was treated with iodine-125 plaque radiotherapy and macula-sparing transpupillary thermotherapy (TTT). Fine needle aspiration biopsy for genetic testing at the time of plaque radiotherapy revealed melanoma with chromosome 3 disomy. This implied lower risk for metastasis than chromosome 3 monosomy or other mutations.3 Following treatment, visual acuity in the left eye was 20/20 in the first year. The tumor regressed to a flat scar of 1.7 mm in thickness by 4 months, and subretinal fluid resolved (Figure 2).
In the August 2009 special issue of Archives of Ophthalmology on ophthalmic pathology, risk factors predictive of growth of small choroidal melanocytic lesions into melanoma were refined.2 The mnemonic TFSOM-UHHD was coined to assist ophthalmologists in the identification of clinical factors that predict small melanoma. These factors include tumor thickness greater than 2 mm, subretinal fluid, symptoms of reduced vision or photopsia, orange pigment, tumor margin less than or equal to 3 mm from the optic disc, ultrasound hollowness, absence of surrounding depigmented halo, and absence of overlying drusen (previously identified by the Collaborative Ocular Melanoma Study Group).2 The presence of each of these features was associated with hazard ratio (HR) of 3 for malignant transformation (Table 1).2 The various combinations of individual risk factors were further evaluated for total predictive power.2 In this case, all eight risk factors were present. These factors do not confirm, but strongly suggest the diagnosis of melanoma. The greater the number of risk factors, the higher the risk for tumor growth, which implies malignancy. 2 For example, a patient with a tumor showing three risk factors had a fivefold risk compared with a tumor without risk factors, a tumor with five factors had a ninefold risk, and one with seven factors had a 21-fold greater risk for growth, likely representing melanoma.2
Risk for long-term metastasis is substantially less with small melanoma compared to large melanoma. In the same ophthalmic pathology issue, one article focused on choroidal melanoma metastasis in more than 8,000 patients and found that metastasis at 10 years occurred in 12% of small melanoma, 26% of medium, and 49% of large melanoma1 (Table 2). In that analysis, specific metastatic risk based on size increase showed about 5% increase in metastasis for each millimeter increase in thickness.1
In the case presented, early intervention with plaque radiotherapy was employed for ocular tumor control and minimization of systemic metastatic disease. In summary, risk factors are important when evaluating a patient with a small melanocytic choroidal tumor as they may allow identification of a life-threatening malignancy at a very early state, perhaps in time before the onset of systemic metastases.1,2
Support provided by the Retina Research Foundation of the Retina Society in Capetown, South Africa (CLS), and the Eye Tumor Research Foundation, Philadelphia, PA (CLS).
Felina V. Zolotarev, BA, is a medical student at Thomas Jefferson University in Philadelphia.
Kiran Turaka, MD, is an Ocular Oncology Fellow at Wills Eye Institute, Thomas Jefferson University.
Carol L. Shields, MD, is the Co-Director of the Ocular Oncology Service, Wills Eye Institute, Thomas Jefferson University. She is a Retina Today Editorial Board member. Dr. Shields can be reached at +1 215 928 3105; fax: +1 215 928 1140; or via e-mail at email@example.com.
The authors have no financial interest on the devices or medications in this document.
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