Ocular Melanoma: Clinical Presentation, Diagnostic Evaluation, Management, and Outcomes – A Case Report

Abstract

Ocular Melanoma is the most common primary intraocular malignancy in adults, arising from melanocytes of the uveal tract, including the iris, ciliary body, and choroid. It is a rare but potentially life-threatening condition due to its high propensity for hematogenous metastasis, particularly to the liver. Early diagnosis remains challenging as initial symptoms may be subtle or absent, leading to delayed presentation.

We report the case of a 55-year-old male presenting with progressive, painless diminution of vision and photopsia. Detailed ophthalmic evaluation and multimodal imaging revealed a pigmented choroidal mass with associated subretinal fluid, consistent with uveal melanoma. The patient was treated with plaque brachytherapy, resulting in tumor regression and stabilization of vision.

This case highlights the importance of early clinical suspicion, appropriate imaging modalities, and multidisciplinary management to optimize outcomes and reduce metastatic risk in patients with ocular melanoma.

Introduction

Uveal Melanoma represents the most common primary intraocular malignancy in adults, with an incidence of approximately 5–7 cases per million per year. The majority of tumors arise from the choroid (~85–90%), followed by the ciliary body and iris. Despite its rarity, uveal melanoma accounts for significant morbidity and mortality due to its aggressive metastatic potential.

The pathogenesis involves malignant transformation of melanocytes, often associated with mutations in GNAQ, GNA11, BAP1, and SF3B1 genes. Tumor growth leads to progressive disruption of retinal architecture and may result in exudative retinal detachment.

Key risk factors include:
• Light iris color and fair skin
• Chronic ultraviolet exposure
• Ocular or oculodermal melanocytosis
• Dysplastic nevus syndrome
• Genetic predisposition

Clinically, patients may present with:
• Blurred or distorted vision
• Photopsia (flashes of light)
• Floaters
• Visual field defects
• Metamorphopsia
• Asymptomatic lesions detected incidentally

Due to the insidious onset and nonspecific symptoms, early diagnosis is often difficult. Delayed detection increases the risk of metastatic dissemination, particularly via hematogenous routes to the liver.

Case Report

Patient History

A 55-year-old male presented to the ophthalmology clinic with:
• Gradual, painless diminution of vision in the right eye for 3 months
• Intermittent flashes of light (photopsia)
• Progressive peripheral visual field loss

There was no history of ocular trauma, surgery, or inflammatory eye disease. The patient had no known systemic comorbidities such as hypertension or diabetes mellitus. There was no family history of ocular malignancy or melanoma.

Clinical Examination

On examination:
• Best-corrected visual acuity: 6/18 (right eye), 6/6 (left eye)
• Intraocular pressure: within normal limits
• Anterior segment: unremarkable

Fundoscopic examination of the right eye revealed:
• A dome-shaped, elevated pigmented lesion in the choroid
• Presence of overlying subretinal fluid
• Areas of orange pigment deposition (lipofuscin)

The left eye examination was normal.

Clinical Evaluation

Differential Diagnosis

The following conditions were considered:
• Choroidal melanoma
• Choroidal nevus
• Metastatic intraocular tumor
• Circumscribed choroidal hemangioma

The presence of subretinal fluid, orange pigment, and progressive visual symptoms strongly suggested malignant transformation rather than a benign lesion.

Investigations

Ophthalmic Imaging
• Fundus photography: confirmed pigmented elevated lesion

• Optical Coherence Tomography: demonstrated subretinal fluid and neurosensory retinal detachment

• B-scan Ultrasonography: revealed a dome-shaped mass with low-to-medium internal reflectivity and acoustic hollowness

• Fluorescein Angiography: showed early hypofluorescence with late leakage

Tumor dimensions measured approximately 8 mm in basal diameter and 4 mm in thickness.

Systemic Evaluation
• Liver function tests: within normal limits
• Abdominal ultrasound: no evidence of hepatic metastasis
• Chest imaging: unremarkable

Diagnosis

Based on clinical findings and imaging characteristics, a diagnosis of choroidal melanoma was established.

Management and Outcome

Management Strategy

A multidisciplinary approach involving ophthalmology, radiation oncology, and medical oncology teams was adopted.

Primary Treatment
• Plaque brachytherapy using Brachytherapy (Iodine-125)

Supportive Management
• Regular ophthalmic monitoring
• Patient counseling regarding visual prognosis
• Surveillance for metastatic disease

Follow-Up and Outcome

At 3 months:
• Reduction in tumor thickness
• Stabilization of visual acuity

At 6 months:
• Resolution of subretinal fluid
• No evidence of tumor progression

At 12 months:
• Significant tumor regression
• No signs of systemic metastasis
• Improved quality of life

Discussion

Pathophysiology

Ocular melanoma arises from uncontrolled proliferation of melanocytes within the uveal tract. Progressive tumor growth leads to:
• Mechanical disruption of retinal layers
• Exudation causing subretinal fluid accumulation
• Increased intraocular pressure in advanced cases

Metastasis occurs predominantly via hematogenous spread, with the liver being the most common site due to its vascular nature.

Diagnostic Challenges

Early diagnosis can be difficult due to:
• Asymptomatic early stages
• Similar appearance to benign choroidal nevi
• Lack of routine screening

Key diagnostic modalities include:
• Fundoscopy
• Ultrasonography (gold standard for intraocular tumors)
• OCT for retinal involvement
• Angiography for vascular patterns

Treatment Considerations

Radiation Therapy
• Brachytherapy remains the standard of care for small to medium tumors
• Provides local tumor control with globe preservation

Surgical Management
• Enucleation is considered for large tumors or those with severe complications

Systemic Therapy
• Immunotherapy and targeted therapy are used in metastatic disease

Complications

Potential complications include:
• Vision loss
• Radiation retinopathy
• Optic neuropathy
• Secondary glaucoma
• Metastatic spread (especially liver)

Prognosis

Prognosis depends on:
• Tumor size and thickness
• Location within the eye
• Genetic mutations (e.g., BAP1)
• Presence of metastasis

Five-year survival rates vary, with localized disease having a relatively favorable prognosis, while metastatic disease significantly reduces survival outcomes.

Conclusion

Ocular melanoma is a rare yet aggressive intraocular malignancy requiring early detection and prompt intervention. This case highlights the importance of recognizing early visual symptoms such as blurred vision and photopsia.

Imaging plays a crucial role in diagnosis, with ultrasonography and OCT providing valuable structural insights. Management requires a comprehensive, multidisciplinary approach involving radiation therapy, regular follow-up, and systemic surveillance.

Strict monitoring for metastatic disease, especially hepatic involvement, is essential in long-term care. Early diagnosis and appropriate treatment can significantly improve visual outcomes and overall survival in patients with ocular melanoma.

References

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