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Melanoma
Melanoma occurs when
melanocytes (pigment cells) become malignant.
Most pigment cells are in the skin; when melanoma starts in the skin,
the disease is called cutaneous melanoma. Melanoma may also occur in the eye
(ocular melanoma or
intraocular melanoma).
Rarely, melanoma may arise in the meninges,
the digestive tract,
lymph nodes, or other areas
where melanocytes are found. Melanomas that begin in areas other than the
skin are not discussed in this booklet. The Cancer Information Service
(1-800-4-CANCER) can provide information about these types
of melanoma.
Melanoma
is one of the most common cancers. The
chance of developing it increases with age, but this disease affects people of
all ages. It can occur on any skin
surface. In men, melanoma is often
found on the trunk (the area between the shoulders and the hips) or the head
and neck. In women, it often develops
on the lower legs. Melanoma is rare in
black people and others with dark skin.
When it does develop in dark-skinned people, it tends to occur under the
fingernails or toenails, or on the palms or soles.
When melanoma
spreads, cancer cells may show up in nearby lymph nodes. Groups
of lymph nodes are found throughout the body.
Lymph nodes trap bacteria,
cancer cells, or other harmful
substances that may be in the lymphatic system. If the cancer has reached the
lymph nodes, it may mean that cancer cells have spread to other parts of the
body such as the liver, lungs, or brain.
In such cases, the cancer cells in the new tumor are still melanoma
cells, and the disease is called metastatic melanoma, not liver, lung, or brain
cancer. |
