Cancers in the eye

Two types of cancers can be found in the eye.

Primary intraocular cancers are cancers that start inside the eyeball. In adults, melanoma is the most common primary intraocular cancer, followed by primary intraocular lymphoma.

In children, retinoblastoma (a cancer arising from cells in the retina) is the most common primary intraocular cancer, and medulloepithelioma is the next most common (but it is extremely rare). These cancers are discussed in our separate document, Retinoblastoma.

Secondary intraocular cancers are cancers that started somewhere else and then spread to the eye. These are not truly "eye cancers," but they are actually more common than primary intraocular cancers. The most common cancers that spread to the eye are breast and lung cancers. Most often these cancers spread to the part of the eyeball called the uvea. For more information on these types of cancers, refer to the specific American Cancer Society documents on these cancers.

Intraocular melanoma (melanoma of the eye)

Intraocular melanoma is the most common type of cancer that develops within the eyeball in adults, but it is still fairly rare. Melanomas of the skin are much more common than intraocular melanomas.

Melanomas develop from pigment-producing cells called melanocytes. When melanoma develops in the eyeball, it is usually in the uvea, which is why these cancers are also called uveal melanomas. About 9 out of 10 intraocular melanomas develop in the choroid (which is part of the uvea). Choroid cells have the same kind of pigment as melanocytes in the skin, so it is not surprising that these cells sometimes form melanomas.

Nearly all of the remaining intraocular melanomas start in the iris. These are the easiest for the patient and doctor to see because they often arise in a pigmented spot on the iris that has been present for many years and then begins to grow. These melanomas usually are fairly slow growing, and they rarely spread to other parts of the body. For these reasons, people with iris melanomas generally have a good prognosis (outlook).

Intraocular melanomas are generally made up of 2 different kinds of cells.

• Spindle cells: These are long, thin cells.
• Epithelioid cells: These cells are almost round but with some straight edges.

Most tumors are composed of both kinds of cells. The outlook is better if the tumors are mostly spindle cells as opposed to mostly epithelioid cells. Epithelioid tumors are more likely to metastasize (spread) to distant sites. If you have intraocular melanoma, your doctor can tell you which type of cells were found.

Primary intraocular lymphoma (lymphoma of the eye)

Lymphoma is a type of cancer that starts in immune system cells called lymphocytes. It usually starts in lymph nodes, which are bean-sized collections of immune system cells. But lymphomas can also start in internal organs such as the stomach, lungs, and rarely in the eyes.

There are 2 main types of lymphoma: Hodgkin disease and non-Hodgkin lymphoma. Primary intraocular lymphoma is always a non-Hodgkin lymphoma. Most people with primary intraocular lymphoma are elderly or have immune system problems such as the acquired immunodeficiency syndrome (AIDS). Primary intraocular lymphoma is often seen along with lymphoma of the brain, known as primary central nervous system (CNS) lymphoma.