Choroidal melanoma is the most common primary malignant tumour we find inside the eye. It differs from melanomas that develop on the eyelids etc. Luckily, it is rare, affecting only 6 people per million (US figures) as it is a very serious eye condition and can lead to death through metastasis.
The choroid is the vascularised layer of the eyeball that lies between the white outer shell (or sclera) and the inner layer (or retina). It is part of the uvea, (which also includes the iris and the ciliary body). Choroidal melanoma is the most common primary malignant tumour we find inside the eye. It most often affects whites of northern European descent.
Signs and symptoms
Choroidal melanomas can develop in the eye without symptoms until they have already metastasised. They may be picked up incidentally in routine eye examinations with your optometrist, who will see a nodular, dome-shaped and well-circumscribed mass under the retina. The colouration can vary from light to dark.
Choroidal melanoma may present with the following symptoms:
• Blurred vision
• Loss of peripheral vision
• Severe ocular pain
If the tumour is secondary to a primary tumour elsewhere in the body, there may also be the following symptoms:
• Weight loss
• Marked fatigue
• Change in bowel or bladder habits
• Liver enzyme levels are indicated in any patient with choroidal melanoma, because the liver is the most common site of choroidal melanoma metastasis
• A-scan ultrasonography of the eye is useful for tumours thicker than 2-3 mm
• Obtain a chest x-ray to rule out possible lung metastases
• CT scanning and MRI may also be useful for larger tumours
Treatment options depend on the size and extent of the tumour.
• Observation may be acceptable for small, easy-to-see tumours where malignancy may not yet be established. They are carefully measured and monitored for any sign of growth.
• Laser and heat therapy can also be used for small tumours.
• For medium sized tumours, radiotherapy can be delivered locally via a small plaque, secured behind the eye at the site of the melanoma. Other types of irradiation are also used.
• Removal of the eye (enucleation) is the classic approach to choroidal melanomas and has been the preferred treatment for large and complicated tumours. Sometimes only part of the eye needs to be removed.
• Systemic chemotherapy is not normally indicated.
• When distant metastases are found in the initial systemic workup, palliative systemic chemotherapy is the primary treatment.