Melanoma is a type of cancer that starts in cells called melanocytes. These cells are found in the skin and produce melanin, a pigment that gives your skin its color. Melanocytes are also found in mucosal tissues, such as the lining of the mouth, nose, and rectum. Melanoma occurs when these cells grow out of control. This type of cancer can spread to other parts of the body if not treated early.
The most common symptom of melanoma is a new spot on the skin or a change in an existing mole.
Changes to watch for include:
Melanoma in mucosal tissues can cause different symptoms, depending on the location. For example, in the mouth, it may appear as a dark patch or lump, while in the rectum, it may cause bleeding or discomfort.
Most cases of melanoma involving the skin are caused by DNA damage related to ultraviolet (UV) exposure from the sun or tanning beds. This damage triggers changes in the melanocytes, causing them to grow uncontrollably.
However, not all melanomas are caused by UV exposure. For example, mucosal melanomas, which occur in areas not exposed to the sun, are thought to be caused by genetic mutations unrelated to UV light. The exact reasons why these mutations occur are still being studied.
Melanoma is a type of cancer that starts in melanocytes. It is one of the most common types of skin cancer. However, because melanocytes are also found in mucosal tissues, melanoma can occur in places like the eyes, oral cavity, and rectum. This means melanoma is not just a type of skin cancer but can also be classified as a type of eye, oral cavity, or rectal cancer.
Melanoma is most often found on parts of the body that are exposed to the sun, such as the face, arms, back, and legs. In men, melanoma is commonly found on the back. In women, it is often found on the legs. Melanoma can also develop in less exposed areas, like the palms, soles of the feet, or under the nails, especially in people with darker skin.
Melanoma can look different from person to person, but it often appears as an irregular mole or spot.
Doctors use the “ABCDE” rule to identify potential melanomas:
The diagnosis of melanoma is made by examining the suspicious spot and performing a biopsy. During a biopsy, a small sample of the tissue is taken and examined under a microscope by a pathologist. If melanoma is found, additional tests may be done to determine if it has spread to other parts of the body.
There are several types of melanoma, including:
Under the microscope, melanoma cells often look larger and more irregular than normal melanocytes. They may have uneven shapes and unusually large nuclei (the center of the cell). Pathologists look for certain patterns, such as cells spreading into deeper layers of the skin or forming clusters. Special stains or tests, like immunohistochemistry, may be used to confirm the diagnosis.