Lesions of the Skin

Skin cancer is the most common form of human cancer. More than 50% of all cancers are skin cancers. The incidence of skin cancer is higher than all other cancers combined. Since 1992, there has been a 300% increase in incidence of skin cancer. Nearly half of all Americans and two thirds of all Australians who live to age 65 will develop skin cancer at lease once. The most common warning indication of skin cancer is a change in the appearance of the skin, such as new growth or a sore that will not heal. About 80% of all skin cancers are basal cell carcinomas, about 16% are squamous cell carcinomas and 4% are melanomas.


Precancerous Growths

A number of abnormal but relatively harmless skin growths constitute the early warning signs of skin cancer. These may be precancerous lesions, benign tumours that mask or mimic more serious ones, or malignant tumours that are at the moment just on the topmost layer of the skin. They are important to recognise, because they are a warning sign of potential skin cancer.

Skin in a precancerous state is abnormal but not malignant. The term “precancerous” is used because these abnormal areas of skin are more likely to turn malignant than healthy skin. Precancerous growths are visible to the naked eye, and they look different from normal cells when they are examined under a microscope.

When malignant changes occur in the skin, but haven’t spread beyond the top layer of the skin, they are called early cancers or cancers in situ. A barrier called the basement membrane helps delay invasion by malignant cells deeper into the skin.


Actinic Keratosis (AK)

Signs and Symptoms

  1. A small crusty, scaly or crumbly bump or horn that arises on the skin surface.
  2. Colour ranging from pink to red to brown, or flesh-coloured; sometimes light grey.
  3. Appear on sun-exposed areas of the body (e.g. face, lips, ears, back of the hands, forearms, scalp, neck).
  4. The scale or crust is horny, dry and rough, and is often recognised by touch rather than sight. Occasionally it itches or produces a prickling or tender sensation.
  5. Usually reaches a size from an eighth to a quarter of an inch (2mm to 4mm) but can sometimes be as large as one inch (25mm).
  6. Early on, it may disappear only to reappear later,it is not unusual to see several AKs at a time.

The lesions are precancerous because without treatment, a percentage of these lesions develop into Squamous Cell Carcinomas (SCCs), which can be very invasive skin cancers. However, not all SCCs develop from AKs. Although the time of progression from AK to SCC is variable, it is advisable to treat all AKs. The American Academy of Dermatology reports the 40% of cases of SCC begin as AKs.

Risk Factors

  1. Pale-skinned, fair-haired, light-eyed people, or those who tend to freckle or burn when exposed to sunlight.
  2. Age over 40 years.
  3. Residence in a sunny climate.
  4. History of frequent or intense sun exposure or sunburn, especially in early life.
  5. History of AK or skin cancer.
  6. Immunocompromised status secondary to chemotherapy, chronic leukaemia, AIDS, or organ transplant medications.
Treatment Options

Basal Cell Carcinoma

Basal Cell Carcinoma (BCC) is the most common form of cancer. Basal cells are cells that line the deepest layer of the epidermis. An abnormal growth – a tumour – of this layer is known as BCC.

Signs and Symptoms

  1. An open sore that bleeds, oozes, or crusts and remains open for three or more weeks. A persistent, non-healing sore is a very common sign of an early BCC.
  2. A reddish patch or irritated area, frequently occurring on the chest, shoulders, arms, or legs. Sometimes the patch crusts. It may also itch or hurt. At other times, it persists with no noticeable discomfort.
  3. A shiny bump or nodule that is pearly or translucent and is often pink, red or white. The bump can also be tan, black or brown especially, in dark-haired people, and it can be confused with a mole.
  4. A pink growth with a slightly elevated rolled boarder and a crusted indentation in the centre. As the growth slowly enlarges, tiny blood vessels may develop on the surface.
  5. A scar-like area which is white, yellow or waxy, and often has poorly defined borders. The skin itself appears shiny and taut. This warning sign can indicate the presence of an aggressive tumour.

BCC can usually be diagnosed by examination under a microscope with a simple biopsy and is fairly easy to treat when detected early. However, 5 to 10 percent of BCCs can be resistant to treatment or locally aggressive, eating away at the skin around them, sometimes even into bone and cartilage.

When not treated quickly, they can be difficult to eliminate. Fortunately, however, this is a cancer that has an extremely low rate of metastasis, and although it can result in scars and disfigurement, it is not usually life-threatening.

Risk Factors

  1. Over-exposure to sun: Intermittent sun exposure like that received during holidays, especially early in life, promotes the formation of BCCs.
  2. Heredity: People with Celtic heritage have an increased risk of skin cancer from the sun. Genetic diseases that affect the skin can also increase the risk. For example, albinism, a genetic condition that prevents the production of normal melanin.
  3. Exposure to certain chemicals: Chemicals can increase the skin’s sensitivity to UV radiation by a process called photosensitization.
  4. Age: Most skin cancers appear after age 50 however, the sun’s damaging effects begin in early childhood.
Treatment Options

Squamous Cell Carcinoma

Squamous cells are cells that compose most of the epidermis. An abnormal growth of these cells is known as SCC. Usually SCCs are slow growing and only spread to other parts of the body if left untreated.

Signs and Symptoms

  1. A wart-like growth that crusts and occasionally bleeds.
  2. A persistent, scaly red patch with irregular borders that sometimes crusts or bleeds.
  3. An open sore that bleeds and crusts and persists for weeks.
  4. An elevated growth with a central depression that occasionally bleeds.
  5. A growth of this type may rapidly increase in size.

Just above the basal layer of cells is a layer known as a prickle layer derived from the upward movement of basal cells to the outer epidermis. SCC develops from the prickle layer just above the basal layer.

New cells push older cells towards the skin’s surface, the older cells die and are sloughed off. This process is controlled by DNA, the body’s genetic material.

When the DNA is damaged, the rate of new cell supply and old cell die off is not in balance. The orderly pattern is disrupted, causing cells to grow out of control resulting in SCC.

Most damage to the DNA of skin cells results from overexposure to UV radiation from sunlight. The damage is cumulative, so childhood sun exposure contributes to the formation of SCC at a much later age.

Risk Factors

  1. Chronic sun exposure
  2. Fair Skin
  3. Age
  4. Personal history of Skin Cancer
  5. Weakened immune system
  6. Smoking
  7. Skin inflammation or injury
  8. Inappropriate diets (low in antioxidants)
Treatment Options