The following sizes are used to describe intraocular melanoma:
The tumor is 5 to 16 millimeters in diameter and from 1 to 3 millimeters thick.
Millimeters (mm). A sharp pencil point is about 1 mm, a new crayon point is about 2 mm, and a new pencil eraser is about 5 mm.
The tumor is 16 millimeters or smaller in diameter and from 3.1 to 8 millimeters thick.
The tumor is:
- more than 8 millimeters thick and any diameter; or
- at least 2 millimeters thick and more than 16 millimeters in diameter.
Though most intraocular melanoma tumors are raised, some are flat. These diffuse tumors grow widely across the uvea.
There are three ways that cancer spreads in the body.
Cancer can spread through tissue, the lymph system, and the blood:
- Tissue. The cancer spreads from where it began by growing into nearby areas.
- Lymph system. The cancer spreads from where it began by getting into the lymph system. The cancer travels through the lymph vessels to other parts of the body.
- Blood. The cancer spreads from where it began by getting into the blood. The cancer travels through the blood vessels to other parts of the body.
Cancer may spread from where it began to other parts of the body.
When cancer spreads to another part of the body, it is called metastasis. Cancer cells break away from where they began (the primary tumor) and travel through the lymph system or blood.
- Lymph system. The cancer gets into the lymph system, travels through the lymph vessels, and forms a tumor (metastatic tumor) in another part of the body.
- Blood. The cancer gets into the blood, travels through the blood vessels, and forms a tumor (metastatic tumor) in another part of the body.
The metastatic tumor is the same type of cancer as the primary tumor. For example, if intraocular melanoma spreads to the liver, the cancer cells in the liver are actually intraocular melanoma cells. The disease is metastatic intraocular melanoma, not liver cancer.
There are two staging systems for intraocular melanoma.