July 16, 2012
MELANOMA
Melanoma is the most common malign tumor of the uvea. It arises primarily from the pigmented cells of the uvea. It looks like a brown flat or protruding nodule.
Melanoma of the iris is usually easy to notice, so it is early revealed, and thus successfully treated. Each new pigmentation in the iris should inspire caution and requires careful monitoring and detection of signs of malignancy – does it grow, does it rise up and is it vascularized.
Melanomas of the other localizations are difficult to detect because the interference can occur very late. Specifically, the patient notices changes in visual acuity only when melanoma affects the central parts of the eye’s background. If the melanoma is located on the far periphery, it can grow very large, and may even have distant metastases, before reaching the central parts of the retina and causes interferences.
Diagnosis of melanoma is set by lightening the eye with Langeov’s Illumination lamp, ultrasonography of the eyeball and fluorescein retinoangiographia.
Diagnosis between melanoma and nevus uvea is very important. Nevus usually does not rise above its surroundings, does not increase, and has no pathological vascularization.
Treatment:
More than a hundred years, enucleation of the eye affected with melanoma was the only method of treatment. Today there are several treatments that are still in the experimental stage, but their results are very encouraging. Very small tumors may be photocoagulated with laser or criocoagulated. Medium-sized tumors (pea-sized) are radiated with brachytherapy or with the cyclotrons. Radiation causes the death of malignant cells and decreasing of the tumors. However, tumors often do not disappear completely. In addition, radiation can damage the lens, retina and optic nerve, causing a gradual reduction of vision.
Brachytherapy (radiation treatment with an open source of radiation) is performed so that on the top of the sclera, above the melanoma, is sewed a little pad with radioactive material. This method is most promising, although there are no long-term test results.
With the cyclotron irradiation, a small metal tag is surgically attached on the eyeball, which then serves as a target for directing the air. For now, this treatment is applied in only a few centers in the world.
There are other treatments still in the test phase; the treatment with the resection of the eyeball, and immunotherapy against melanoma.
HEMANGIOMA
Although hemangiomas can be found on any part of the uvea, the most common are on the choroid.
They may be associated with hemangiomas in other regions as a part of the syndrome Sturge – Weber. They usually do not rise much over the environment and are blurrily limited from the surrounding normal vascular tissue of the choroid. Diagnosis is made by fluorescein angiography and ultrasoography.
Treatment:
If at all necessary, tumor is photocoagulated with a laser.