Melanoma in the skin cancer clinic
Detecting an early melanoma is a very rewarding outcome of a checkup at the skin cancer clinic. Every effort should be made for an early diagnosis of malignant melanoma. But there are different types and they come in all different shapes and sizes.
Why is Melanoma so important?
- Australia has the second-highest rate of melanoma in the world.
- The overall rate of melanoma in Australia is still increasing, and has almost doubled in the last 34 years.
- Melanoma is the 4th most common cancer in Australia (other than the non melanoma skin cancers).
- Early diagnosis is curative.
- Melanoma can easily be mistaken for benign skin lesions.
Who is at risk of melanoma?
The strongest risk factors are:
- Family history (brother, sister, mother, father or child affected)
- Lots of moles (eg. More than 100)
- Large “atypical moles”
- Previous melanoma
Other risk factors are:
- Red hair, blue eyes, skin that easily burns
- History of blistering sunburn
- Previous use of sunbeds
- Being on immunosuppressant medication
Age is the biggest risk factor for melanoma. The gap between rates of melanoma in younger and older people is increasing. Nevertheless, younger people still get melanoma, with a rate of 9.4 cases per 100,000 reported in 2016.
Can I tell if I have a melanoma?
Around half of melanomas develop in a pre-existing mole, and the other half occur spontaneously. So you need to keep an eye out for both changing lesions, and new lesions. A changing lesion is one that has a change in any of the following: Area, Border, Colour, Diameter or thickness (The ABCDE algorithm – E is for Elevation).
Become familiar with your own skin and look for changes in shape, colour, size, and outline. Be wary of a new lesion – easier said than done for lesions on the back, so look with a mirror, use a smartphone camera or ask a partner. It’s really important to understand that any change is important because some malignant melanomas get lighter and not darker. Melanoma may not be pigmented. Indeed, melanoma may be entirely pink.
The skin cancer doctor will greatly refine the probability of melanoma with dermatoscopy at a skin check. Dermatoscopy examination has two benefits
- A skin lesion that looks fine with the “naked eye” may be concerning after dermatoscopy.
- A skin lesion that might otherwise look “nasty” may be entirely reassuring after dermatoscopy.
What types of melanoma are there?
Superficial Spreading Melanoma (SSM): The most common and best known type of melanoma. The melanoma spreads horizontally in the upper layers of the skin before eventually growing vertically. This type of melanoma is most common on the back in men, and on the leg in women. This type of melanoma accounts for 55-60% of melanoma, and is the type most often occurring in younger people. SSM can grow over months or years, particularly in the horizontal growth phase. The melanoma appears fairly flat and is usually pigmented.
Amelanotic Melanoma: Appear to have no pigment whilst Hypomelanotic melanoma is partially pigmented.
Nodular Melanoma: as the name suggests, this type of melanoma is elevated. These melanomas tend to be aggressive and any elevated growing lesion must be taken seriously. Around half of nodular melanomas appear to have little or no pigment – they’re just pink or skin coloured growths. In fact, around 90% of nodular melanoma seen through a dermatoscope does have at least some pigment.
The rule of thumb for nodular melanoma is to get any growng pink lesion that has not gone within a month checked out urgently
Lentigo maligna and lentigo malignant melanoma: These are most commonly found on sun exposed areas of the head and neck. They are flat, like superficial spreading melanoma. However, this type of melanoma is harder to spot. The melanoma tends to blend into the background sun-damaged skin and to look like a brown patch. Lentigo maligna affects only the upper layer of skin (epidermis) and may grow for many years before growing down into the dermis when it is called lentigo maligna melanoma.
Acral Melanoma (acral lentiginous melanoma) account for around 1-2% of melanoma in Australia. This type of melanoma is not related to sun exposure, and occurs on the sole of the feet, palms of the hands, or nail-bed. This is the reason why a full skin check does involve a look at the soles of the feet. Darker skin such as people of Asian or African descent are at greater risk.
Desmoplastic melanoma. This type of melanoma is rare and easily missed – it tends to be felt as a firm lesion on the head or neck in older people, and may arise from lentigo maligna.
It should be emphasised that Nodular melanoma may be particularly dangerous. They are generally rapidly growing red nodules and may not appear to have any pigment or brown in them at all. These cause 15% of melanomas but around 45% of melanoma deaths. They are more likely to be deep melanomas, are faster growing and more likely to spread.