The first sign of a melanoma is often a new mole or a change in the appearance of an existing mole. Normal moles are generally round or oval, with a smooth edge, and usually no bigger than 6mm in diameter. But size is not a sure sign of melanoma. A healthy mole can be larger than 6mm in diameter, and a cancerous mole can be smaller than this. Credit: Anagramm / Thinkstock //www.istockphoto.com/gb/photo/melanoma-gm498526384-79692191 The stock library no longer exists. Image was incorporated into the webpage during the subscription term and can be used indefinitely in the same page - subject to thinkstock subscription rules.More info is at the bottom of this page regarding ThinkStock licensing: //confluence.service.nhs.uk/display/VP/Photography+stock+sites See a GP as soon as possible if you notice changes in a mole, freckle or patch of skin, particularly if the changes happen over a few weeks or months. Credit: Scott Camazine / Alamy Stock Photo //www.alamy.com/stock-photo-melanoma-skin-cancer-with-coloring-of-different-shades-of-brown-black-30211255.html?pv=1&stamp=2&imageid=205D301A-1083-47F1-AE4D-0C1D6C284E21&p=9949&n=0&orientation=0&pn=1&searchtype=0&IsFromSearch=1&srch=foo%3dbar%26st%3d0%26pn%3d1%26ps%3d100%26sortby%3d2%26resultview%3dsortbyPopular%26npgs%3d0%26qt%3dBN46NB%26qt_raw%3dBN46NB%26lic%3d3%26mr%3d0%26pr%3d0%26ot%3d0%26creative%3d%26ag%3d0%26hc%3d0%26pc%3d%26blackwhite%3d%26cutout%3d%26tbar%3d1%26et%3d0x000000000000000000000%26vp%3d0%26loc%3d0%26imgt%3d0%26dtfr%3d%26dtto%3d%26size%3d0xFF%26archive%3d1%26groupid%3d%26pseudoid%3d788068%26a%3d%26cdid%3d%26cdsrt%3d%26name%3d%26qn%3d%26apalib%3d%26apalic%3d%26lightbox%3d%26gname%3d%26gtype%3d%26xstx%3d0%26simid%3d%26saveQry%3d%26editorial%3d1%26nu%3d%26t%3d%26edoptin%3d%26customgeoip%3d%26cap%3d1%26cbstore%3d1%26vd%3d0%26lb%3d%26fi%3d2%26edrf%3d0%26ispremium%3d1%26flip%3d0%26pl%3d Signs to look out for include a mole that's: The ABCDE checklist should help you tell the difference between a normal mole and a melanoma: Melanoma can appear anywhere on your body, but they most commonly appear on the back in men and on the legs in women. It can also develop underneath a nail, on the sole of the foot, in the mouth or in the genital area, but these types of melanoma are rare. In rare cases, melanoma can develop in the eye. It develops from pigment-producing cells called melanocytes. Eye melanoma usually affects the eyeball. The most common type is uveal or choroidal melanoma, which grows at the back of the eye.Melanoma of the eye
Very rarely, it can grow on the thin layer of tissue that covers the front of the eye (the conjunctiva) or in the coloured part of the eye (the iris).
Noticing a dark spot or changes in vision can be signs of eye melanoma, although it's more likely to be diagnosed during a routine eye examination.
The pictures below have been provided by the St John’s Institute of Dermatology at Guy’s and St Thomas’ Hospital.
These pictures are just a guide. Without further tests, it's not possible to work out what is a melanoma or not. If you’re worried about any moles or skin changes, it is always important to get them checked by your GP.
Melanoma that has developed from a suspicious dark mole
Suspicious irritated mole found not to be melanoma
Melanoma from a mole that was once an even colour and shape but has now changed
Melanoma from a mole with changing shape and colour
Melanoma that has developed from a long standing mole that is starting to spread
A new change to an area of skin (lesion) that was abnormal and turned out to be melanoma
Doctors sometimes use the term lesion to describe a finding on the skin. This means an area of skin that looks different from the surrounding area.
Melanoma on the back
The following 2 examples contain 2 pictures. The first picture in each example is taken from a distance. The second picture from each example is a close up of the melanoma.
Example 1 - Picture of a melanoma from a new, dark lesion on the skin
Example 2 - Picture of melanoma that may or may not have developed from a mole
Melanoma that has developed from a changing area of the skin with an irregular shape and colour
The blue markings in this picture below outline the area where the melanoma is. This is to show the surgeon the area they need to remove.
Melanoma that hasn't developed from a mole and is starting to spread
- Find out more about seeing your GP if you are worried
Last reviewed:
18 Jul 2022Next review due:
18 Jul 2025Print page
Page Credits
With special thanks to Dr Theodoulos Drousiotis at the St John’s Institute of Dermatology at Guy's and St Thomas' NHS Foundation Trust for sourcing the photographs of the different types of melanoma and pictures of abnormal moles and skin changes.