Tumours of the Uveal Tract

Tumours of the uveal tract are divided into benign and malig­nant. Benign tumours are cysts, nevus, neuromas, leiomiomas.

Choroidal nevus. A benign pigmental tumour of the choroid, which mostly develops in adults. Unlike malignant melanomas, there are no retinal degeneration, and visual field defects. Fluo­rescent angiography doesn't reveal the tumour.

Treatment is not needed. The tumour should be followed up in dynamics, because its malignization is possible.

Malignant melanomas of the iris. Dispite the tumours of the iris may have slow growth, it is necessary to conduct surgical remov­al in time. If growth has been documented and there is danger of the tumour spreading into the ciliary body, removal of the tumour and the surrounding healthy iris is usually all that is required.

Malignant melanomas of the ciliary body are much more ag­gressive and require urgent treatment. When the tumour has not spread to the choroid or through into the anterior chamber, a lo­calized removal may be considered (cyclectomy).

Malignant melanomas of the choroid. These pigmental tumours, which tend to occur in the older age group and may appear at the age of 30-40, but extremely rare before puberty. In transcleral il­lumination in the area of the tumour a shadow in the pupil is ob­served.

Diagnosis is confirmed by growth of a pigmented tumour, the uptake of the radioactive phosphorus in the area of the tumour, by ultrasonography and by means of the fluorescent angiographic studies, which demonstrate the presence of a pathological circula­tion. As vision may not be involved until a late stage and no symp­toms are noticed, the tumour can become relatively large before the patient is aware of any visual problems. The tumour, which is gray-brown in color, either spreads within the choroid, or breaks through the Bruch's membrane to become nodular or fungiform, so that eventually it can be seen through the pupil.

Metastases are spread by blood flow, giving rise to secondary growths in many organs, principally the liver, bones, lung and brain.

Treatment. Small tumours can be treated by X-ray therapy, light coagulation, cryotherapy or local excisions. Eyes with larger tu­mours should be removed providing no metastases can be found in other organs. Prognosis depends upon the degree of cellular dif­ferentiation of the tumour and it's size. Small well-differentiated tumours have a good prognosis and may be observed for long pe­riods without apparently altering the life expectancy of patient. With tumours larger than 10 mm in a diameter that are highly un­differentiated, or where there is evidence of extrascleral extensions or metastases the prognosis is poor.

Dystrophy of the Uveal Tract

Essential mesodermal atrophy of the iris. This is a unilateral pro­gressive condition, beginning not earlier than the third decade of the life. The iris undergoes atrophy and becomes transparant. Poly-coria appears, the pupil displaces, the eversion of the pigment leaf of the iris occurs; the total aniridia is possible. Secondary glauco­ma is a frequent and serious complication.

Treatment is symptomatic, intended for improvement of tro­phism.

The Fuchs' syndrome is characterized by 3 signs: terochromia, precipitates, the secondary glaucoma.

Treatment is symptomatic.

Glaucomocyclic crisis. Young people mostly men are affected. Rise of IOP, decreasing of the visual acuity, oedema of the cor nea, precipitates of the corneal posterior surface are typical signs. The attack lasts from some hours to 1-2 weeks.

Date: 2014-12-21; view: 1276