UVEAL TUMORS - II. Melanoma choroideae

The wall of the eye has 3 main layers. From outside to inside there is: the white sclera, a blood vessel layer called the uvea (choroid, ciliary body and iris) and an inner retinal layer. Further, the pigment producing cells, “melanocytes” are primarily found in the vascular uveal layer. It is those melanocytes that can turn into malignant melanoma. Therefore, when melanoma happens in the choroid, they are called “choroidal melanoma,” the most common primary intraocular malignancy in adults. That said, choroidal melanomas are rare with 5 to10 out of each million people diagnosed with a choroidal melanoma each year. Choroidal melanomas can spread to other parts of the body.

Eye cancer specialists can determine if you have a choroidal melanoma by performing a complete eye examination with testing. This includes asking questions about your medical history, examining both of your eyes, looking into the eye through a dilated pupil, performing an ultrasound examination, and specialized photography (to examine the circulation within the choroidal melanoma).

Most choroidal melanoma patients have no symptoms. 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.

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).
Choroidal melanoma can leak fluid beneath the retina, making the retina detach and cause symptoms of flashing lights and floating specks “floaters”.
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). In general, the earlier and smaller the choroidal melanoma, the better the prognosis for both life and sight.

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.

Most choroidal melanoma patients have no symptoms. 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.

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).
Choroidal melanoma can leak fluid beneath the retina, making the retina detach and cause symptoms of flashing lights and floating specks “floaters”.
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). In general, the earlier and smaller the choroidal melanoma, the better the prognosis for both life and sight.

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.

Therapy

Small Choroidal Melanoma (stage 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. If growth is documented (typically within 6 months of observation), eye cancer specialists will typically 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. palladium-103). However, larger tumors require more radiation and larger irradiated intraocular volumes resulting in greater risk of radiation side-effects and poor vision. Rarely such eyes have to be secondarily removed. Eye cancer specialists try to preserve eyes, even if the eye had reduced vision.

Large-sized Choroidal Melanoma (stage T3 - T4):
Very large choroidal melanomas (greater than 22 mm width) may be treated by initial removal of the eye (enucleation). This is because the amount of radiation required to destroy a choroidal melanoma that fills most of the eye will likely be too much for the eye to tolerate.

However, most patients, even with very large-sized choroidal melanoma can be treated with eye-sparing radiation therapy. However, after eye sparing radiation for very large choroidal melanomas, eyes are at greater risk to have poor vision, secondary inflammation and may require secondary eye globe enucleation (removal) later.

 

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