MGL Skin Cancer Clinic | About Skin Cancer
All skin cancers are malignant and all malignancies are cancers, of one type or another.
Skin Cancer, early detection, common types skin cancer, basal cell cancers, squamous cell cancers, melanomas
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About Skin Cancers
Are Skin Cancers Malignant?

Yes – all skin cancers are malignant.
And all malignancies are cancers, of one type or another.
Any “benign” skin lesion is not a skin cancer.

All skin cancers are malignant and all malignancies are cancers, of one type or another.
What are the Common Types of Skin Cancers?
  1. Basal Cell Cancers (BCC’s)
  2. Squamous Cell Cancers (SCC’s)
  3. Melanomas – by definition, all Melanomas are Malignant Melanomas
What Should I Know About Basal Cell Cancers (BCC’s)
  1. BCC’s are the commonest cancers (of all types), in fair-skinned people.
  2. They start in the “basal” layer of the epidermis
  3. Almost all of them are caused by UV sun damage
  4. BCC’s are malignant or cancerous only in the area in which they occur, as a general rule -; ie, they rarely spread to other parts of the body
  5. Some BCC’s can grow very large and “ulcerate” – these used to be called rodent ulcers” because it looked as if a rat had been nibbling away at the flesh. Thankfully, we rarely see these now
  6. BCC’s have several different growth patterns, the main ones being:
    – Superficial
    – Nodular
    – Cystic
    – Infiltrating
    – Sclerosing / Morphoeic
  7. Superficial and nodular BCC’s are mostly on the surface, so that what you see is the diameter of the lesion and they can vary in depth into the skin
  8. Infiltrating and morphoeic BCC’s are potentially a bigger problem, because what is seen on the surface may be only part of the problem. They can burrow or infiltrate beneath the surface of the skin and so can be much larger than it looks from on top.
  9. BCC’s are usually pink in color, but some may contain some blackish spots / areas ( and are therefore termed “pigmented BCC”). Some may even be indistinguishable in color from the surrounding skin, but have a “sheen” when looked at with the correct light. They may be slightly or significantly raised from the surface, but also may be flat or even slightly depressed below the surface of the skin.
What Should I Know About Squamous Cell Cancers (SCC’s) ?
  1. SCC’s, like BCC’s, are almost always caused by UV sun damage. The sun damages; the skin cell DNA allowing mutations to arise that causes the cells to become cancerous.
  2. However, smoking not only produces premature ageing of the skin with wrinkly dry skin, but causes a lot of SCC’s on lips and in the mouth. These SCC’s are more dangerous, in that they can spread to lymph nodes and other parts of the body.
  3. SCC’s arise from the epidermis or outer layer of the skin, as do BCC’s.
  4. Most SCC’s occur on the body sites that are most exposed to the sun, especially face, scalp, ears, neck, arms, back, legs.
  5. Some SCC’s are potentially more life-threatening than BCC’s, in that a small proportion will spread to other parts of the body, in particular lymph nodes. In Australia in 2008, 420 people died from non-melanoma skin cancer, and most of these were from SCC’s. There were 279 males, and 141 females.
  6. A lot of SCC’s develop from pre-existing sunspots (sometimes called actinic or solar keratoses), and some develop as SCC’s from the start.; We usually treat sunspots so that they do not progress into SCC’s.
  7. SCC’s become more common as we get older, and this has a lot to do with our immune systems becoming less efficient in dealing with new cancer cells that develop. Another significant cause of SCC’s is immune system suppression which occurs in people who have had an organ transplant or suffer from certain “auto-immune” diseases & are on medications designed to block the human immune system from working as well. Other disease processes, smoking and excessive alcohol consumption also contribute to the formation of SCC’s.
  8. SCC’s are more likely to be tender or sore, than other types of skin cancer.
  9. An interesting relative of an SCC is the Keratoacanthoma. It is a fast growing tumor that develops over a couple of months, and occurs on any part of the body, most often in sun-exposed sites. They can reach up to 2cm in size or more, often with a central “crater-like” plug of keratin, and roughly circular. Sometimes they will disappear by themselves, sometimes not. The Pathologist has trouble sometimes in differentiating a Keratoacanthoma (KA) from an SCC.; They are quite common.
  10. SCC’s have the following classifications :-
  11. Superficial or intra-epithelial, meaning it is still confined to the epidermis (these are sometimes known as Bowen’s Disease)
  12. Invasive, which means they have penetrated deeper into the skin, and may be well-differentiated, moderately differentiated or poorly-differentiated with the latter being the worst type.
What Should I Know About Melanomas ?

Firstly, let’s talk about the pigment cells, called “melanocytes

  1. Melanocytes are different from the other types of skin cells, in that they originate from what is called the “neural crest” in the developing fetus, and not from the “ectoderm” which gives rise to the other skin cell types and structures. By about the third to fourth month of pregnancy, the melanocytes migrate to the area where the skin cells are developing, and the mature melanocytes take up their position in the basal layer of the epidermis.
  2. So, do dark-skinned people have more melanocytes in the epidermis than fair-skinned people? Interestingly, no. We all have the same number of pigment cells, but there is a genetic difference in the type of melanin or pigment produced.; Dark-skinned people produce more of a type of melanin called Eumelanin that has black and brown forms. This type of melanin is responsible for skin and hair color that is dark brown to black, and is the predominant melanin in dark-skinned people. On the other hand, fair skinned people have a predominance of Pheomelanin which is yellowish to reddish, and hence people of fair to red complexion.; The enormous range of skin colors in humans is therefore a result of genetic proportioning of these two types of melanin.
  3. So why do dark-skinned people not get as many skin cancers?; The reason is that the Eumelanin in their skin is an excellent natural sun-blocking agent. This melanin makes its way up through the epidermis, attached to other cells, and shields the DNA inside the nuclei of these cells from damaging UV radiation.

Now let’s find out a few facts about Melanomas.

  1. Melanomas are malignant, by definition ie they are a type of skin cancer.; There is no benign melanoma
  2. In 2008,; 1437 people died from melanoma in Australia – 965 men and 472 women.
  3. Apart from BCC’s & SCC’s, Melanomas are the fourth most common cancers affecting Australians ( following bowel, breast & prostate). In 2006, there were 10,326 Australians diagnosed with melanoma – 6,051 males and 4275 females.
  4. Melanoma is the most common cancer in people aged 15 – 44 years. Australian adolescents have by far the highest incidence of melanoma in the world. Melanomas account for one third of all cancers in adolescent Australian females, and one quarter of all cancers in adolescent Australian males.
  1. Australia has the highest incidence of melanoma in the world.
  2. Melanomas can occur on any part of the skin in the human body. Up to 10% of melanomas occur on skin that has never seen the sun, including the genitals and vagina.; In the six years to early 2012, Dr Sadler has diagnosed 250 melanomas at the Skin Cancer Clinic in Taree, with the site distribution for men and women indicated in the graph
    below.
  1. Melanoma characteristics :-
    1. Most melanomas are caused by UV radiation exposure damaging the DNA of the melanocytes (pigment cells).; Multiple severe sunburns, particularly in childhood, are a significant factor, as is chronic sun exposure. These melanomas start on the surface of the skin.; However, some melanomas start from cells that have not been sun-damaged, and other factors that are as yet not clearly identified are obviously involved.
    2. Some melanomas are flat and some are raised above the surface of the skin.
    3. The colors of melanomas may be black, light or dark brown, variegated with black/brown/bluish/white areas, pink, red, whitish.
    4. Melanomas may arise from a pre-existing mole, or start as a new spot.
    5. Some melanomas are relatively slow growing, some very fast.; The fast ones are usually much more dangerous.
    6. Melanomas are classified as to how far they have penetrated into the skin – the earliest stage is where the melanoma is still confined to the epidermis or top layer of the skin and these are termed “Melanoma in-situ”. From there, there are 2 classification systems usually commented on by Pathologists and these are basically an indication of how far the melanoma cells have penetrated into the deeper layers of the skin.; The deeper the penetration into the dermis, the greater the likelihood of cells spreading to other parts of the body.
    7. Survival rates for people who have had a melanoma treated adequately are very good for thinner melanomas, ie less than 1mm in thickness,; but decline with increasing thickness.
    8. Early detection and treatment are the keys to best outcomes of melanoma patients.
  1. Melanoma Treatments :-
    1. Surgery is still the main-stay of treatment of melanoma – usually local treatment at the site of the melanoma is in two stages, The first stage is the excision of the suspected area with a small eg 2mm margin – this is sent to the Pathologist for diagnosis plus, in the case of the lesion being a melanoma, how far it has penetrated into the skin. The second stage is further wider excision of where the melanoma was, with the intent of getting clearance of the edges of the melanoma of 5mm in the melanoma in-situ variety, and 10 – 20mm clearance in “thicker” melanomas.
    2. Sentinel Lymph Node Biopsy is a further step.; Virtually every area of the body is serviced by “lymph” – a body fluid distinct from blood, with its own network of lymph vessels. Lymph from each area of the body drains to one or more “lymph nodes” commonly situated in the groins, along the spine of abdomen and chest, in the armpits (axillae), and around the neck. Lymph draining from the area where a melanoma was excised can usually be tracked to one or more of these lymph nodes which can then be surgically removed & examined under the microscope to see if there has been any spread of the melanoma to these glands.; This gives a good idea of “staging” of the melanoma, but is usually only done for “thicker” melanomas.
    3. If a melanoma has spread to other parts of the body, sometimes surgery is used in its treatment.
    4. Radiotherapy with X-Rays is occasionally used.
    5. Vaccines have been tried with limited success, using genetic material from the melanoma.
    6. Medications have been used
      1. topically, that is applied to the skin
      2. systemically, that is take by mouth or administered by injection

 

    Some of these medications show great potential, and in the next decade or so, may well be used effectively in advanced melanoma disease.