Melanoma of the ciliary body
Overview
Malignant melanoma that originates in the ciliary body is termed, "ciliary body melanoma." The ciliary body is located immediately behind the iris and in front of the choroid. Therefore, it is hidden behind the iris. It is responsible for making the aqueous fluid that fills the front of the eye. The ciliary body is highly vascular and contains the melanocytes from which melanomas can grow. Compared to iris and choroidal melanoma, ciliary body melanoma is the most difficult to find.
Symptoms
Ciliary body melanoma patients usually have no symptoms. When symptomatic, patients present with an irregular astigmatism (due to the tumor pushing on the natural lens), sector cataract, tumor in the visual axis (line of vision) or secondary glaucoma.
Diagnosis
Ciliary body melanoma patients may present with a new astigmatism that is difficult to refract. Slit-lamp examination may reveal a "sentinel" episcleral vessel or evidence of extrascleral extension. Relatively small ciliary body melanomas are sometimes found by gonioscopy of the anterior chamber angle. Ophthalmic oncologists have found high-frequency ultrasound to be extremely valuable for the evaluation of ciliary body melanoma. Previously hidden behind the iris, even small ciliary body melanomas are being uncovered. Three hundred sixty degrees of ciliary body should be inspected during each high-frequency ultrasound examination of a ciliary body melanoma. Ciliary body melanomas can grow completely around the eye to become a "ring melanoma." Ring melanoma is highly associated with secondary glaucoma, different colored irises (heterochromia) and extrascleral tumor extension.
Treatment
Most ciliary body melanoma can be treated like choroidal melanoma. Small Ciliary Body Melanoma: Patients with a small ciliary 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 tumor growth prior to treatment. Small ciliary body melanoma are typically treated by local resection or radiation therapy. Medium-sized Ciliary Body Melanoma: Around the world, most patients with a medium-sized ciliary melanoma are treated with either radiation therapy, surgery or removal of the eye. Almost all patients prefer not to lose their eye when eye and vision-sparing treatment options are available. Though the results of the Collaborative Ocular Melanoma Study (COMS) suggest that plaque radiation therapy and enucleation of the eye are equally effective for the prevention of metastatic choroidal melanoma, patients with ciliary body melanoma were not included in the COMS. Large-sized Ciliary Body Melanoma: A patient with a very large ciliary body melanoma is likely to be treated by removal of the eye (enucleation). This is because the amount of radiation required to kill a tumor which fills most of the eye, is just too much for the eye to tolerate. Patients with very large ciliary body melanoma can also be treated with eye-sparing radiation. The risks are that many of these eyes will become uncomfortable, have poor vision, and may have to be removed later.