The type of eye cancer you have depends on the type of cell the cancer started in.
Eye cancers are called ocular cancers. Ocular is the medical name for the eye.
Cancers affecting the inside of the eye are intraocular. Those affecting the outside of the eye are extraocular.
Cancers of the eyeball
Intraocular cancers include:
The cells that become cancerous in melanoma are called melanocytes. Melanocytes are cells that make pigment or colouring. There are melanocytes in our skin, lips, and the lining of organs such as the eye.
Most melanomas start in the skin but they can also develop in other parts of the body including the eye.
Melanoma of the eye can start in the:
- eyeball (globe)
- conjunctiva (covering of the front of the eyeball)
Doctors also group melanomas of the eyeball according to the way the cancerous cells look under a microscope. There are 3 types:
- spindle cell melanomas – made from long stretched out cells
- non spindle cell melanomas (epithelioid) – made from round or oval cells, which are harder to treat and more likely to spread to other parts of the body
- a mix of spindle and non spindle cells
You usually have surgery or radiotherapy, or both to treat melanoma of the eyeball.
Uveal or choroidal melanoma
Melanoma starting in the eyeball is rare, but it is the most common type of eye cancer in adults. Your specialist may call it uveal or choroidal melanoma because it grows in the tissues in the middle layer of the eyeball, the choroid. This layer is sometimes called the uvea, and includes the iris and ciliary body.
The melanoma starts in the choroid in more than 9 out of 10 cases (90%) of eyeball melanoma. The rest begin in the iris and ciliary body.
Iris melanomas are usually easy to spot, so doctors often diagnose them when they are in their early stages. They are usually slow growing and rarely spread to other parts of the body.
Conjunctiva and eyelid melanoma
Melanoma of the conjunctiva and the eyelid are extraocular cancers and they are extremely rare. They are treated slightly differently to melanoma in the eyeball.
Lymphoma usually begins in the lymph nodes, which are part of your immune system.
Very rarely lymphoma begins inside the eyes. This is called primary intraocular lymphoma. Intraocular lymphomas are always a type of non Hodgkin lymphoma. You are more likely to have intraocular lymphoma if you have a weakened immune system. For example, people who:
- have AIDS
- have had organ transplants and need to take drugs to damp down their immune system
- are elderly
Intraocular lymphoma is generally treated in the same way as a lymphoma anywhere else in the body.
There are two main types of cancers of the eyeball that develop in children. These are:
Retinoblastoma is a rare type of eye cancer that nearly always occurs in children under the age of 5.
Medulloepithelioma is a very rare type of eye tumour found most often in young children. It does not usually spread. Treatment is surgery to remove the tumour. Occasionally, this will involve removing the eye.
Squamous cell cancer of the conjunctiva
Squamous cells are flat and cover many surfaces in the body. The conjunctiva is the clear, moist membrane that covers the front of the eye and lines the inside of the eyelid. Although rare, squamous cell cancer is the most common cancer of the conjunctiva.
This cancer usually grows on the surface of the conjunctiva but can grow into and around the eye. It is generally slow growing (low grade), and very rarely spreads to another part of the body.
Treatment includes surgery to remove the cancer, freezing therapy (cryotherapy) and chemotherapy eye drops (topical chemotherapy).
Abnormal cells on the surface of the conjunctiva is called conjunctival intraepithelial neoplasia or CIN. If you have this you may have topical chemotherapy on its own. If left untreated, CIN may turn into invasive squamous cell cancer.
Cancers around the eyeball
The areas around the eyes are the orbit and the accessory muscles. Cancers that develop in these parts of the eye are cancers of muscle, nerve and skin tissue.
Basal cell skin cancer
A cancer of the eyelid is usually a type of skin cancer called basal cell cancer. Doctors treat it like any other basal cell skin cancer.
Rhabdomyosarcoma is a rare type of cancer that can start in the muscles that move the eye, usually in children.
Secondary eye cancers
Sometimes cancer can spread to the eye from another part of the body. This is called a secondary eye cancer. In women this is most likely to happen with breast cancer, and in men lung cancer.