Mucosal melanoma is a rare form of melanoma that occurs in mucous membranes. These are the moist surfaces that line the cavities within our body. Melanomas that appear on mucous membranes and the skin (cutaneous melanoma) start when melanocytes turn cancerous. Apart from this shared origin, mucosal melanoma and skin melanoma differ substantially in their behaviour and biology.
For example, a known risk for developing skin melanoma is a history of exposure to the sun, especially during childhood. However, this does not increase the risk of mucosal melanoma. In fact, there are presently no risk factors, including family (genetic) susceptibility, or environmental causes like UVB exposure that can be linked to mucosal melanoma in research studies.
Mucosal melanomas can also be more complicated to treat than skin melanomas. One significant reason for this is they are often diagnosed at a later stage. They tend to occur in less visible places and are not always pigmented (darker), which makes them even more difficult to spot.