Malignant Melanoma of the uvea
Definition
Uveal melanoma is a cancer (melanoma) of the eye involving the iris, ciliary body, or choroid (collectively referred to as the uvea).
Epidemiology:
While development of uveal melanoma is largely considered to be a sporadic event, certain risk factors including iris colour, skin colour, ability to tan, northern European ancestry, and rarely a family history of uveal melanoma have been reported to predispose individuals to uveal melanoma.
Aetiology:
It arises from melanocytes in the choroid, ciliary body, or iris.
Clinical presentation:
It's characterized by nonspecific findings associated with the location of the tumour: A) posterior choroidal tumours present with decreased: 1)visual acuity 2) floaters 3) photopsia 4) visual field defects.
B) Tumours involving the iris often present with the patient complaining of iris colour changes or other externally observed iris abnormalities.
Treatment:
The primary goal of treatment for uveal melanomas is to prevent metastasis, this is accomplished for all uveal melanomas by enucleation, which provided a histological diagnosis and guided further treatment, when necessary. Radiation therapy is also a therapeutic option which is accompanied with different complications
Prognosis:
Prognosis varies for uveal melanoma depending on: the patient’s age, the size of the tumour, the cell type seen on histology (spindle A cells associated with the best prognosis and epithelial cells the worst), histological characteristics (meiotic activity, lymphocytic infiltration, fibrovascular loops) the location of the tumour (with melanomas involving the ciliary body conferring the highest risk of metastasis), and the extent of metastasis.