The causes of eye cancer & Signs and Symptoms of Eye Melanoma

 

causes eye cancer

The exact cause of most eye cancers is not known. But scientists have found that the disease is linked with some other conditions, which are described in the section “What are the risk factors for eye cancer?” A great deal of research is being done to learn more about the causes.

Scientists are learning how certain changes in the DNA inside cells can cause the cells to become cancerous. DNA is the chemical in each of our cells that makes up our genes, the instructions for how our cells function. We usually look like our parents because they are the source of our DNA. But DNA can also influence our risk for developing certain diseases, such as some kinds of cancer.

Some genes control when our cells grow, divide into new cells, and die. Genes that help cells grow, divide, or stay alive are called oncogenes. Genes that slow down cell division or cause cells to die at the right time are called tumor suppressor genes. Cancers can be caused by DNA changes that turn on oncogenes or turn off tumor suppressor genes.

Some people with cancer have DNA changes they inherited from a parent that increase their risk for the disease. For example, some people inherit a change (mutation) in the BAP1 tumor suppressor gene, which increases their risk of eye melanoma and some other cancers. When the BAP1 gene is mutated, it doesn’t work normally, which can allow cells with this change to grow out of control.

Most DNA changes linked to cancer are acquired during life rather than inherited before birth. For example, recent research has shown that about 4 out of 5 eye melanomas have changes in either of 2 related genes, GNA11 or GNAQ, which appear to be oncogenes. Other, as of yet unknown, gene changes are probably needed for these cancers to develop as well.

Scientists are studying these and other DNA changes to learn more about them and how they might lead to eye cancer. But it is still not exactly clear what causes these changes to occur in some people and not others.

Signs and symptoms of eye lymphoma

The possible signs and symptoms of eye lymphomas include:

    #Blurred vision or loss of vision
    #Seeing floaters (spots or squiggles drifting in the field of vision)
    #Redness or swelling in the eye
    Sensitivity to light
    #Eye pain (uncommon)

Intraocular lymphoma most often affects both eyes, but it can cause more symptoms in one eye than in the other.

Most of these symptoms are more likely to be caused by other, less serious conditions. For example, floaters can occur as a normal part of the aging process. Still, if you have any of these symptoms, it’s important to see a doctor right away so the cause can be found and treated, if needed.

Many of the exams and tests mentioned below are described in more detail in the section “How is melanoma of the eye diagnosed?”

Eye exam

The doctor will ask about any symptoms you are having and may check your vision and eye movements. During the eye exam, the doctor will use an ophthalmoscope (an instrument with a light and a small magnifying lens) to get a good look inside the eye. If lymphoma is present, the doctor may see that the vitreous (the jelly-like substance that fills most of the inside of the eye) is cloudy.

Imaging tests

Imaging tests use sound waves, x-rays, or magnets to create pictures of the inside of your body.

Ultrasound: Ultrasound is usually done to determine the size, shape, and location of the mass (tumor), especially if the back of the eye can’t be seen during the eye exam.

Magnetic resonance imaging (MRI) scan: An MRI of the head is often done not only to see the eye better, but also to look for lymphoma in the brain or meninges (the thin layers of tissue that cover the brain and spinal cord), which are common sites of spread of this cancer.

Computed tomography (CT) scan: CT scans are used less often than MRI scans for eye lymphoma because they do not provide as much detail.

Positron emission tomography (PET) scan: If a lymphoma has been found, a PET scan can help give the doctor a better idea of whether it has spread to lymph nodes or other parts of the body. A PET scan can also be useful if your doctor thinks the cancer might have spread but doesn’t know where.

For this test, a form of radioactive sugar (known as fluorodeoxyglucose or FDG) is injected into a vein (IV). (The amount of radioactivity is very low and will pass out of the body over the next day or so.) Because cancer cells in the body are growing rapidly, they absorb more of the radioactive sugar. After about an hour, you are moved onto a table in the PET scanner. You lie on the table for about 30 minutes while a special camera creates a picture of areas of radioactivity in the body. The picture is not as detailed as a CT or MRI scan, but it can provide helpful information about whether abnormal areas seen on these tests are likely to be cancer.

Many centers have special machines that can do both a PET and CT scan at the same time (PET/CT scan). This lets the doctor compare areas of higher radioactivity on the PET scan with the more detailed appearance of that area on the CT scan.

For more information on imaging tests, see our document Imaging (Radiology) Tests.

Biopsy

Symptoms and the results of exams and tests might suggest you have intraocular lymphoma, but a biopsy is usually needed to confirm the diagnosis. To biopsy the eye, an ophthalmologist most often does a procedure called a vitrectomy. You may be sedated and get local anesthesia (numbing medicine) or you may get general anesthesia (which puts you in a deep sleep).

The doctor takes a sample of the vitreous gel from inside the eye by inserting very small instruments into the eye, cutting the vitreous, and then sucking some of it out. The cells in the biopsy sample are then sent to a lab to be looked at under a microscope and tested by other special techniques. For more information on the lab tests done on suspected lymphoma specimens, see our document Non-Hodgkin Lymphoma.

Lumbar puncture (spinal tap)

This test is used to look for lymphoma cells in the fluid that surrounds the brain and spinal cord (called cerebrospinal fluid or CSF). It is done in cases of known or suspected eye lymphomas because these cancers often affect the brain or spinal cord.

For this test, you lie on your side with your knees up near your chest. The doctor first numbs an area in the lower part of the back near the spine. A small, hollow needle is then placed between the bones of the spine to withdraw some of the fluid.

The fluid is then examined under a microscope for lymphoma cells. Other tests may be done on the fluid as well.



Source By.........http://www.cancer.org/cancer/eyecancer/detailedguide/eye-cancer-lymphoma-diagnosis