By Paul T. Finger, MD
Malignant “choroidal” melanoma arise from the blood-vessel layer “choroid” beneath the retina. In North America, 6 out of each million people will be diagnosed with a choroidal melanoma each year. Malignant choroidal melanomas can spread to other parts of the body.
Eye cancer specialists determine if you have a choroidal melanoma by performing a complete eye examination. This includes asking questions about your medical history, examining both of your eyes, looking into the eye through a dilated pupil at the tumor, performing an ultrasound examination, and specialized photography (to examine the circulation within the choroidal melanoma).
Your specialist will also request that you have a complete general medical check up and specific tests depending upon what they see inside your eye. Eye cancer specialists can correctly diagnose an intraocular choroidal melanoma in over 96% of cases (without a biopsy).
Classic indications for biopsy include: atypical tumor, metastatic tumor with no observable primary cancer and when the patient requires a pathology diagnosis. However, due to genetic testing, more and more centers are routinely performing choroidal tumor biopsies. These biopsies are meant to obtain both pathology confirmation and prognostic information. However, biopsy dose carry some risk of hemorrhage, infection, retinal detachment, and tumor seeding (outside the eye). Risks related to tumor seeding are thought to be small, but clearly they have not been evaluated by any large prospective or retrospective study. On the other hand, the results of biopsy have not changed current treatment nor need for follow up evaluations. Each eye cancer specialist should discuss the relative risks (known and unknown) of biopsy prior to surgery.
Most choroidal melanoma patients have no symptoms and the melanoma is found on routine eye examination. If patients have choroidal melanoma symptoms, they are usually seeing “flashes of light,” noticing “distortion” or loss of vision, and floating objects (floaters) in their vision.
1) If the choroidal melanoma is in the front of the eye (near the natural lens), it can push or tilt the natural lens causing an irregular astigmatism (blurring of vision).
2) Choroidal melanoma can leak fluid beneath the retina, making the retina detach and cause symptoms of flashing lights and floating specks.
3) If the choroidal melanoma is in the macula (center of vision), it can grow beneath the fovea making the patient far-sighted. The choroidal melanoma can also grow into and destroy the fovea causing distortion, loss of vision or changes in color perception.
It is important to note that most patients with choroidal melanoma have no symptoms at all. Their tumors are found when they visit their eye doctor for a “routine” eye examination. So everyone should have periodic eye examinations (including dilated ophthalmoscopy).
Other, more unusual presentations of anterior choroidal and iridociliary melanoma are discoloration of the iris, a brown spot on the outside of the eye, an irregularly shaped pupil and glaucoma.
Choroidal melanoma can be seen by ophthalmoscopy (when your eye doctor looks through a lens into your dilated pupil).
Choroidal melanoma has typical “diagnostic” characteristics that include but are not limited to: pigmentation, thickness, low or moderate internal ultrasound reflectivity, orange pigment on its surface, and leakage of fluid or retinal detachment (on or around the choroidal melanoma).
1) Choroidal melanoma pigment is due to naturally occuring melanin that comes from melanocyte cells in the choroidal layer. Choroidal melanoma is usually pigmented, but can be variably pigmented and even amelanotic (non-pigmented). Non-pigmented choroidal melanoma is due to a proliferation of melanocytes that have lost their ability to make melanin pigment.
2) Orange pigment (lipofuscin) on the choroidal melanoma indicates that cells are dying on the tumor’s surface. This is a sign of metabolic activity.
3) Ultrasound is typically used to measure the choroidal melanoma size, evaluate internal tumor reflectivity, and look for melanoma extension behind the eye into the orbit (extrascleral extension). Ultrasound shows that most choroidal melanomas are shaped like a dome and less commonly like a mushroom. Ultrasound can also evaluate choroidal melanoma associated retinal detachment.
Small Choroidal Melanoma (AJCC T1 and T2):
Patients with a small choroidal melanoma can be treated after their first visit, but since growth helps to prove that the tumor is a cancer, your doctor may suggest “observation” or watching for a small amount of choroidal melanoma growth prior to treatment. Your eye cancer specialist should discuss the relative risks and potential benefits of “observation for growth” as compared to “immediate treatment” for choroidal melanoma. Once growth is documented (typically within 6 months of observation), eye cancer specialists will recommend definitive treatment.
Medium-sized Choroidal Melanoma (AJCC T3 and T4):
Most patients with large-sized choroidal melanoma can be also be treated with eye-sparing low energy radiation therapy (e.g. iodine-125 or palladium-103). After radiation for large choroidal melanoma, these eyes are at greater risk to have poor vision, to become uncomfortable and may have to be secondarily removed. However, most patients would prefer to keep their eye even if it has or develops poor vision.
Patients with a very large choroidal melanoma (greater than 22 mm width) may be treated by removal of the eye (enucleation). This is because the amount of radiation required to destroy a choroidal melanoma that fills most of the eye may be too much for the eye to tolerate.
Large-sized Choroidal Melanoma:
A patient with a very large choroidal melanoma may be treated by removal of the eye (enucleation). This is because the amount of radiation required to destroy a choroidal melanoma that fills most of the eye may be too much for the eye to tolerate.
However, most patients with large-sized choroidal melanoma can be also be treated with eye-sparing radiation therapy. After radiation for large choroidal melanoma, these eyes are at greater risk to have poor vision, to become uncomfortable and may have to be secondarily removed.
It is important to note that as compared to like-sized malignant melanoma of the skin, patients are much more likely to survive a choroidal melanoma. This is because it is much more difficult for a choroidal melanoma to spread from (get out of) the eye to other parts of the body. However, large (choroidal melanoma) tumor size decreases the chance that vision-sparing treatments will be successful. In general, the larger the choroidal melanoma the worse the prognosis for both vision and metastasis.
Dr Finger suggests you protect your eyes from ultraviolet radiation. He says, “Think of Sunglasses as Sun Block for your Eyes” ™
Patients often ask why they have a choroidal melanoma. Choroidal melanoma is more common among patients with blue vs. brown eyes, those with outdoor occupations and in Australia where there is an ozone hole. Therefore, it seems reasonable to assume (though unproven) that choroidal melanoma is related to sunlight (ultraviolet exposure). In that sunlight exposure has been linked to several eye cancers and diseases of the eye, Dr. Finger suggests that you “Think of Sunglasses as Sun Block for your Eyes” ™ and start wearing your UV blocking sunglasses. They make great gifts too!
- View photographs of choroidal melanoma, choroidal nevus and other choroidal tumors
- View ultrasound images of choroidal melanoma and other ocular tumors
- A comparison of plaque versus proton radiation for choroidal melanoma
- A comparison of iodine-125 versus palladium-103 eye plaque radiation therapy
- What some patients look like after enucleation for choroidal melanoma
- Read about the “Finger Classification of Radiation Retinopathy” and how it predicts vision loss.
- An overview of treatments for metastatic choroidal melanoma
- Images related to radiation therapy for choroidal melanoma
- An article about PET/CT to monitor for metastastic choroidal melanoma
- Why choroidal melanoma specialists should use a standardized classification “language.”
- Ocular prosthesis care after enucleation for choroidal melanoma
- Scientific articles about choroidal melanoma written by Dr. Finger
- The Collaborative Ocular Melanoma Study (COMS): What is it? What did it show?
- Dr. Finger shows how three-dimensional (3D) ultrasound can be used to make sure the plaque is placed correctly
- Frequently asked questions about choroidal melanoma
- Frequently asked questions about enucleation for choroidal melanoma
- Other patients with choroidal melanoma can be found on our bulletin board
- Learn more about The New York Eye Cancer Center’s approach to treatment of choroidal melanoma
- To Treat or Not to Treat – The Small Choroidal Melanoma Controversy