A choroidal lesion is any abnormal growth or area of change in the choroid, the blood-vessel-rich layer that sits between the retina and the white outer wall of the eye. Most choroidal lesions are benign, with the choroidal nevus, essentially an eye freckle, being by far the most common. Roughly one in twenty American adults over 40 has one, and most will never know it unless an eye doctor spots it during a routine exam. But the term “choroidal lesion” covers a wide spectrum, from harmless freckles to metastatic cancer, and the path from discovery to diagnosis can be confusing for patients who hear the phrase for the first time.
The Choroidal Nevus
A choroidal nevus is a flat or slightly raised collection of pigment-producing cells in the choroid. Think of it as a mole inside the eye. These are usually discovered incidentally during a dilated eye exam, because they rarely cause symptoms on their own. A large study of U.S. adults aged 40 and older found that about 5% have a choroidal nevus in the back portion of the eye.1Current Opinion in Ophthalmology. Choroidal nevus: a review of prevalence, features, genetics, risks, and outcomes Most nevi are small, slate-gray or brownish, and sit quietly for decades without growing or causing trouble.
When your eye doctor photographs a nevus and asks you to come back in six months, they are not suggesting it is dangerous right now. They are establishing a baseline so that any future change can be detected early. A long-term study tracking elevated nevi with ultrasound found that the vast majority, over 300 lesions followed for a median of six years, showed no growth or change whatsoever.2American Journal of Ophthalmology. Long-term Echographic Surveillance of Elevated Choroidal Nevi Still, a small fraction of nevi do eventually transform into melanoma, and distinguishing a sleepy freckle from one that might wake up is one of the central puzzles in ocular oncology.
Risk Factors for a Nevus Becoming Melanoma
Eye specialists use a set of clinical and imaging features to gauge how likely a nevus is to grow into something malignant. A study of over 3,800 nevi identified the most predictive warning signs and organized them into the mnemonic TFSOM-DIM: thickness greater than 2 mm on ultrasound, subretinal fluid on optical coherence tomography (OCT), symptoms such as significant vision loss, orange pigment visible on autofluorescence imaging, acoustic hollowness on ultrasound, and a tumor diameter over 5 mm on photography.3Retina. CHOROIDAL NEVUS IMAGING FEATURES IN 3,806 CASES AND RISK FACTORS FOR TRANSFORMATION INTO MELANOMA IN 2,355 CASES
The more of these features a nevus has, the higher its five-year risk of transformation. A nevus with none of these risk factors had roughly a 1% chance of becoming melanoma over five years. One risk factor pushed the estimate to about 11%, two factors to around 22%, and three factors to about 34%. With four or five of these features present, the five-year risk climbed above 50%.4Retina. CHOROIDAL NEVUS IMAGING FEATURES IN 3,806 CASES AND RISK FACTORS FOR TRANSFORMATION INTO MELANOMA IN 2,355 CASES This steep gradient is why monitoring recommendations depend so heavily on how many features a nevus displays. A flat, quiet nevus with no risk factors can usually be checked once or twice a year after an initial baseline period. A nevus with one or two features warrants checks every four to six months. Three or more features should prompt evaluation at a specialized center, where treatment may be considered rather than continued watching.5JAMA Ophthalmology. Choroidal Nevus Transformation Into Melanoma: Analysis of 2514 Consecutive Cases
Choroidal Melanoma
Choroidal melanoma is the most common primary cancer that originates inside the eye in adults. Unlike skin melanoma, which is driven by mutations in genes like BRAF and NRAS, uveal melanoma has a distinct genetic profile. About 85% of uveal melanomas carry mutations in either the GNAQ or GNA11 gene, which occur in a mutually exclusive pattern, meaning a tumor typically has one or the other but not both.6PubMed Central. GNAQ and GNA11 Genes: A Comprehensive Review on Oncogenesis, Prognosis and Therapeutic Opportunities in Uveal Melanoma7British Journal of Cancer. Mutation frequencies of GNAQ, GNA11, BAP1, SF3B1, EIF1AX and TERT in uveal melanoma: detection of an activating mutation in the TERT gene promoter in a single case of uveal melanoma These mutations are considered the initiating event that pushes a choroidal cell toward becoming cancerous, though they do not by themselves determine how aggressive the tumor will be.
Prognosis depends heavily on a different genetic marker: the status of chromosome 3 in the tumor. Loss of one copy of chromosome 3 (called monosomy 3) is strongly associated with metastatic spread. In a long-term follow-up study, the disease-specific death rate was about 75% for tumors with monosomy 3, compared with roughly 13% for tumors that retained both copies of the chromosome.8British Journal of Cancer. Prognostic significance of chromosome 3 alterations determined by microsatellite analysis in uveal melanoma: a long-term follow-up study This is why biopsy of choroidal tumors has become increasingly common, not just to confirm whether a lesion is melanoma, but to determine its genetic profile and predict the risk of spread.9PubMed Central. Choroidal biopsies; a review and optimised approach.
Choroidal Hemangioma
Not all choroidal lesions involve pigment cells. A circumscribed choroidal hemangioma is a benign vascular tumor, a tangle of blood vessels that usually appears as an orange-red dome in the back of the eye. It typically shows up in middle-aged adults and, unlike a nevus, tends to cause symptoms. Decreased vision is the most common complaint, reported by around 80 to 90% of patients.10PubMed Central. Circumscribed choroidal hemangioma: An overview of clinical manifestation, diagnosis and management11PubMed. Clinical features, diagnosis, management, and prognosis of circumscribed choroidal hemangioma The vision loss comes not from the tumor itself being dangerous, but from fluid that leaks underneath the retina, and in longstanding cases, from changes to the retinal tissue overlying it.
Hemangiomas are often mistaken for more worrisome lesions. In a series of 200 consecutive patients, nearly a third were initially referred with a diagnosis of choroidal melanoma, and about one in ten was thought to be a metastasis from cancer elsewhere in the body.12PubMed. Circumscribed choroidal hemangioma: clinical manifestations and factors predictive of visual outcome in 200 consecutive cases This overlap in appearance is one reason why imaging is so important for distinguishing between types of choroidal lesions. When treatment is needed, photodynamic therapy (PDT) has become a mainstay. In multiple studies, PDT flattened the tumor and resolved the subretinal fluid in most cases, with vision stabilizing or improving in roughly 80% of treated patients.13PubMed Central. Photodynamic therapy of circumscribed choroidal haemangioma14PubMed. DOUBLE FLUENCE PHOTODYNAMIC THERAPY FOR THE TREATMENT OF CIRCUMSCRIBED CHOROIDAL HEMANGIOMA
Choroidal Osteoma
Among the more unusual benign choroidal lesions is the choroidal osteoma, a plate of mature bone that forms within the choroid. It is rare, tends to affect young women more than other groups, and can sometimes be felt as a hard, calcified mass on ultrasound. The bone itself is not the problem. Vision loss occurs through three routes: breakdown of the retinal pigment layer overlying areas where the bone has decalcified, fluid buildup under the retina, and most frequently, the growth of abnormal new blood vessels through or over the bony surface.15PubMed Central. Review of choroidal osteomas Imaging with OCT angiography has shown that the tiny blood vessel layer called the choriocapillaris stays intact in calcified areas of the osteoma but is lost wherever decalcification has occurred, which helps explain why decalcification leads to progressive vision decline.16Journal of VitreoRetinal Diseases. Optical Coherence Tomography Angiography Detects Choriocapillaris Loss in Decalcification of Choroidal Osteoma
Choroidal Metastases
The choroid is the most common place in the eye for cancer from somewhere else in the body to land. Its rich blood supply makes it a natural destination for circulating tumor cells. The two cancers that spread to the choroid most frequently are breast cancer and lung cancer, which together account for roughly 60 to 70% of all cases.17PubMed Central. Choroidal metastases: origin, features, and therapy After those, kidney, gastrointestinal, and thyroid cancers round out the list, though nearly any solid tumor can metastasize to the eye.18PubMed Central. Uveal Metastasis: Clinical Features and Survival Outcome of 2214 Tumors in 1111 Patients Based on Primary Tumor Origin
The pattern of metastasis often gives a clue to the source. Breast cancer tends to produce bilateral, multifocal deposits, meaning both eyes are affected with multiple tumors. Lung cancer metastases more often appear as a single lesion in one eye.19PubMed Central. Choroidal metastases: origin, features, and therapy On ultrasound, lung-derived metastases tend to be dome-shaped and less reflective, while breast-derived lesions are more plateau-shaped and more reflective.20PLOS ONE. Clinical and ultrasonographic features of choroidal metastases based on primary cancer site: Long-term experience in a single center In about one out of six patients, the eye lesion is discovered before anyone knows where the primary cancer is, making the eye finding the first sign of a systemic malignancy.21PubMed Central. Uveal Metastasis: Clinical Features and Survival Outcome of 2214 Tumors in 1111 Patients Based on Primary Tumor Origin For patients with a known cancer history, the appearance of blurred vision or visual distortion warrants a prompt dilated eye exam.
Inflammatory Choroidal Lesions
Not every choroidal lesion is a tumor. A group of inflammatory conditions, sometimes gathered under the umbrella term “white dot syndromes,” produces multiple small yellowish-white spots across the retina, retinal pigment layer, and choroid.22PubMed Central. A review of the inflammatory chorioretinopathies: the white dot syndromes The cause of most of these conditions remains unknown, and for decades they were classified mainly by how they looked on clinical examination. Newer imaging tools, particularly indocyanine green angiography and enhanced-depth OCT, have made it possible to classify them by what is actually happening in the tissue rather than just by their appearance, leading to more precise diagnoses and better-targeted treatment.23PubMed Central. Clinicopathology of non-infectious choroiditis: evolution of its appraisal during the last 2-3 decades from “white dot syndromes” to precise classification Infections such as tuberculosis, toxoplasmosis, and syphilis can also create focal choroidal lesions, typically with accompanying signs of inflammation that help distinguish them from tumors.
How Imaging Tells Lesions Apart
Because so many different conditions can produce a bump or discoloration in the choroid, imaging plays an outsized role in diagnosis. Three modalities are workhorses in this area: ultrasound, OCT, and fluorescein or indocyanine green angiography.
Ultrasound gives a cross-sectional view of the eye and is particularly useful for measuring tumor thickness and detecting internal characteristics. Choroidal melanomas classically show “acoustic hollowness,” a pattern of low internal reflectivity on ultrasound, which contrasts with the more uniform echoes seen in benign nevi. The frequency of the ultrasound probe matters: a 20 MHz probe detects hollowness in more melanocytic tumors than the standard 10 MHz probe, improving specificity for smaller lesions.24PubMed. Detecting ultrasonographic hollowness in small choroidal melanocytic tumors using 10 MHz and 20 MHz ultrasonography: a comparative study
Enhanced-depth OCT has become especially valuable for distinguishing small melanomas from nevi. When comparing melanomas and nevi of similar size, melanomas were more likely to show subretinal fluid, disruption of photoreceptor layers, and a characteristic finding called “shaggy photoreceptors,” irregular outlines along the photoreceptor layer that were present in about half of small melanomas but absent in nevi.25PubMed. Enhanced depth imaging optical coherence tomography of small choroidal melanoma: comparison with choroidal nevus Each tumor type also has a distinct OCT reflectivity signature. Amelanotic (non-pigmented) nevi appear as a medium-bright, uniform band with visible choroidal vessels underneath. Pigmented nevi and melanomas create a bright band at the front of the choroid that blocks the view of deeper structures. Hemangiomas produce a medium-to-low reflective band without that blocking effect. Metastases appear as a low-reflective band deeper in the choroid, sometimes with widening of the space above the sclera.26American Journal of Ophthalmology. Optical Coherence Tomography Enhanced Depth Imaging of Choroidal Tumors
Treatment of Choroidal Melanoma
For most medium-sized choroidal melanomas, plaque brachytherapy is the standard treatment. A radioactive disc is sutured to the outside of the eye wall directly over the tumor and left in place for several days, delivering a focused dose of radiation. It is effective at controlling the tumor locally, but the surrounding retinal tissue inevitably absorbs some radiation, and side effects accumulate over years. In a large series of 650 patients with tumors near the optic nerve, the five-year rate of radiation-related retinal damage was about 66%, and more than half of patients had vision of 20/200 or worse by five years.27PubMed. Plaque radiotherapy for juxtapapillary choroidal melanoma: treatment complications and visual outcomes in 650 consecutive cases These numbers reflect tumors in a particularly challenging location near the nerve, but they illustrate a real tension in treatment: controlling the cancer often comes at a significant cost to vision.
When choroidal melanoma does metastasize, it most frequently goes to the liver and has historically been very difficult to treat. For decades, no systemic therapy showed a clear survival benefit. That changed with tebentafusp, a bispecific protein that directs immune cells to attack melanoma cells. In a randomized trial, one-year survival was 73% in the tebentafusp group compared with 59% in the control group.28PubMed. Overall Survival Benefit with Tebentafusp in Metastatic Uveal Melanoma With longer follow-up at three years, survival was 27% with tebentafusp versus 18% with the investigator’s choice of other treatments.29PubMed Central. Three-Year Overall Survival with Tebentafusp in Metastatic Uveal Melanoma Tebentafusp only works in patients whose immune cells carry a specific tissue type (HLA-A*02:01), which limits its use to roughly half the population, but it was the first therapy to demonstrate a clear overall survival advantage in metastatic uveal melanoma. Follow-up data from a separate cohort of previously treated patients showed that patients whose circulating tumor DNA cleared by nine weeks on treatment had markedly better outcomes, with three-year survival reaching 45% in that subgroup.30PubMed Central. Long-term survival follow-up for tebentafusp in previously treated metastatic uveal melanoma
When a Nevus Causes Problems Without Becoming Cancer
A nevus does not have to become melanoma to threaten your vision. Occasionally, abnormal new blood vessels grow at the surface of a nevus, a process called choroidal neovascularization. These fragile vessels leak fluid or blood under the retina and can mimic an inflammatory condition. Case reports have shown that injections of anti-VEGF drugs such as bevacizumab or ranibizumab into the eye can control this leakage and preserve or restore vision, though recurrences may happen months or years later.31PubMed Central. Choroidal neovascularization secondary to choroidal nevus simulating an inflammatory lesion32PubMed. Intravitreal ranibizumab for choroidal neovascularization secondary to choroidal nevus33PubMed Central. Treatment of vascular activity secondary to atypical choroidal nevus using intravitreal bevacizumab OCT is particularly useful in these situations because it can detect small pockets of fluid that might not be visible on clinical examination, allowing doctors to catch and treat neovascularization early.
Living With a Choroidal Lesion Diagnosis
Being told you have something growing inside your eye is unsettling, even when the doctor reassures you it is almost certainly benign. For patients with a confirmed melanoma, the psychological burden can be substantial. In a study of quality of life among choroidal melanoma patients, the most common severe concern was worry about the cancer coming back, reported by about 41% of patients. Vision impairment was noted by 81%, and two-thirds reported ongoing eye irritation.34PubMed Central. Quality of Life Concerns in Patients with Uveal Melanoma after Initial Diagnosis Interestingly, overall quality of life in melanoma patients was comparable to healthy samples on several measures, though patients who had undergone enucleation (eye removal) scored worse on vision-related quality of life. Patients with unmet informational and supportive-care needs reported worse outcomes across the board, including more depressive symptoms.35PubMed Central. Quality of Life and Cancer-Related Needs in Patients with Choroidal Melanoma The practical takeaway is that clear communication from your care team, understanding your monitoring schedule, and knowing what each imaging visit is looking for, can tangibly reduce anxiety.
Choroidal Melanoma in Children
Uveal melanoma is overwhelmingly an adult disease, but it does occur in children. A multicenter meta-analysis found 133 pediatric patients with ocular melanoma, of whom half had choroidal or ciliary body tumors. The average age at diagnosis was about 7 years. An association with ocular melanocytosis, a congenital condition in which there is excess pigmentation in the eye and surrounding skin, was found in about 15% of the choroidal/ciliary body cases.36PubMed. Pediatric ocular melanoma: a collaborative multicenter study and meta-analysis A more recent case series from Germany and Austria documented 12 children with uveal melanoma over about a decade. In one case, genetic testing revealed Li-Fraumeni syndrome, a hereditary condition that greatly increases cancer risk across many organs.37PubMed. Melanoma of the Choroid and Ciliary Body in Children: Remission of Metastatic Melanoma of the Choroid After Treatment With Chemotherapy and Immune Checkpoint Inhibition This finding underscores that when melanoma appears in a child, genetic testing for underlying tumor-predisposition syndromes is warranted.
Artificial Intelligence in Choroidal Lesion Diagnosis
Distinguishing a small melanoma from a benign nevus on imaging can challenge even experienced specialists, and there is growing interest in whether artificial intelligence can help. Early work using deep-learning models trained on OCT images has shown promising results. One model based on the YOLO11n-cls architecture, tasked with classifying OCT scans into three categories (melanoma, nevus, and normal fundus), achieved correct classification rates of roughly 95 to 97% for each category on a test dataset.38Modern technologies in ophtalmology. An artificial intelligence model for the classification of OCT images of choroidal melanoma and choroidal nevi A follow-up study using the same architecture and incorporating heat-map analysis, which highlights what parts of the image the algorithm focuses on, found an overall accuracy of about 88% and confirmed that the model was relying on the same OCT features that human clinicians consider meaningful, such as disruption of retinal layers and subretinal fluid.39Modern technologies in ophtalmology. Neural network model for OCT image classification and explainable artificial intelligence in the differential diagnosis of choroidal melanoma and choroidal nevi These tools are still in the research stage rather than standard clinical practice, but they suggest that AI-assisted screening could eventually reduce the number of ambiguous cases that require repeated visits or invasive biopsy.