How Melanoma Spreads

The way a cancer grows, or the way it tends to spread (metastasize) if it leaves the site of the original tumor, is called its pathophysiology. If melanoma grows at the site of the original tumor, it tends to grow in one of 2 ways.

• Radial growth. This means the melanoma spreads horizontally along the skin. This kind of growth is a sign of a less aggressive cancer.

• Vertical growth. This means melanoma grows into deeper layers of skin. This kind of growth suggests a more aggressive melanoma.

Melanoma’s growth to distant areas of the body is somewhat unpredictable. It tends to spread first to lymph nodes in the area of the original tumor. For example, if the tumor was on the leg, it may spread to lymph nodes in the groin area. But, sometimes melanoma may spread to distant areas of the body even if the lymph nodes have not been involved.