Author: Vanessa Ngan, Staff Writer; Copy Editor: Clare Morrison; Chief Editor: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, October 2013. About Melanoma is sponsored by the New Zealand Dermatological Society Incorporated.
Melanocytes normally make a pigment called melanin.
Some different skin types are shown below.
|Skin burns. Does not tan||Skin burns easily. Tans poorly||Skin sometimes burns. Tans easily||Light brown skin. Rarely burns|
There are several different types of melanoma. The differences between them determine what a melanoma looks like, how quickly it will grow, where it appears on the body and who is most likely to get one.
Thin melanomas include:
|Superficial spreading melanoma||Lentigo maligna||Lentiginous melanoma||Acral lentiginous melanoma|
Thick melanomas include:
|Nodular melanoma||Amelanotic nodular melanoma||Spitzoid melanoma||Desmoplastic melanoma|
The behaviours of different types of melanoma vary according to the melanomas’ relationship to sun damage.
In New Zealand, melanoma often affects people who are sun damaged. This type of melanoma:
Melanoma can also affect people who actually don't spend a lot of time outdoors. This type of melanoma is associated with earlier sunburn, and:
|Chronic sun damage*||Close-up of melanoma*||Many and unusual moles^||Close-up of melanoma^|
Even people with very little exposure to the sun can get melanoma. Melanoma that is not associated with sun exposure:
Melanoma that starts in other parts of the body is much less common than melanoma that starts in the skin. These types of melanoma can grow quickly and are sometimes hard to diagnose.
Mucosal melanoma starts within a mucous membrane. These are the moist linings that cover body cavities and passages such as the mouth, nose and eyelids, and urinary and genital tracts.
Melanoma may rarely start growing in melanocytes within the eye (uveal melanoma), the brain or spinal cord, the lymph glands, or elsewhere.
Melanoma is often described as primary or secondary.
Primary melanoma is the first sign of melanoma. It starts invisibly small within the skin (or rarely within another tissue) and grows over weeks to years.
|Nodular melanoma||Superficial spreading melanoma||Lentigo maligna||Nail melanoma|
Secondary melanoma is the sign that melanoma has spread to other tissues. This is also called advanced melanoma or metastatic melanoma. Secondary melanoma tends to grow quickly (often noticeable over several weeks).
Deposits of metastatic melanoma may grow within lymph nodes (glands) in the neck, armpit or groin. They may also grow within the skin, brain, lungs, liver or other organs.
In about 3% of patients presenting with secondary melanoma (metastasis), the primary tumour is never found.
Metastatic melanoma is detected clinically on examination or by PET-CT scan.
|Secondary melanoma in the skin||Melanoma under the skin||Melanoma in lymph glands||PET-CT scan:|
metastasis glows in groin
What is melanoma video (Dr Tina Tian)
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