About Skin Cancer

Types of Skin Cancer

Cancer is a disease of the cells, thus skin cancer is a disease of our skin cells.

There are several types, including:

Basal Cell Carcinoma

Basal cell carcinoma (BCC), the most common type of skin cancer, begins in the basal cells in the deepest layer of skin. BCC can develop anywhere, though it is most commonly found in sun exposed areas. While it is possible to have more than one BCC, it is rare for BCC to spread.

Watch our informative video about basal cell carcinoma here.

There are several subtypes of BCC:

  • The most common subtype of BCC is nodular BCC, which often appears as a raised lesion with blood vessels on top. It usually appears on the face.
  • The second most common subtype is superficial BCC, which takes the form of a red, scaly patch. It often develops on the torso and limbs.
  • In the deeper layers of skin, infiltrative BCC can occur. Infiltrative BBC often occurs in the neck and head regions, and takes the appearance of scar tissue.
  • Morpheaform or sclerosing BCC usually occurs in the neck and head regions, and takes the appearance of a flat, firm lesion lacking a defined border.

Source: Canadian Cancer Society, “Basal Cell Carcinoma

Squamous Cell Carcinoma

Squamous cell carcinoma (SCC), which begins in the keratinocyte cells,  is the second most common skin cancer. While SCC usually develops in areas that have been exposed to the sun, it can also manifest in burn or wound sites. SCC is capable of spreading from the surface to deeper layers of skin, lymph nodes or organs.

Watch our informative video about squamous cell carcinoma here.

There are two subtypes of SCC, Adenoid SCC and Desmoplastic SCC, which may have a higher chance of recurrence. Both subtypes often occur on the head or neck, and Adenoid SCC appears as a nude, brown, pink or red nodule.

Source: Canadian Cancer Society, Squamous Cell Carcinoma

Merkel Cell Carcinoma

Merkel Cell Carcinoma (MCC) is a rare non-melanoma skin cancer. It develops in the merkel cells, which are found in the deepest areas of the epidermis and hair follicles. Merkel cells are related to nerve function and hormones production. MCC generally spreads quickly, and develops in areas often exposed to the sun (head, neck, arms, and legs). MCC is sometimes referred to as neuroendocrine skin cancer or trabecular carcinoma.

Watch our informative video about merkel cell carcinoma here.

MCC generally manifests in a non-painful firm, raised bump on the skin, which may be red or purple in colour. As MCC spreads more bumps may appear nearby, and swelling may occur in the lymph nodes.  

Source: Canadian Cancer Society, “Merkel Cell Carcinoma“.

Melanoma

Melanoma begins as a malignant tumour in the melanocytes, which are the cells that produce melanin or pigment. As a malignant cancer, melanoma can metastasize to other parts of the body. There are several subtypes of melanoma, including cutaneous, mucosal, and ocular melanoma.

Watch our informative video about melanoma here.

Source: Canadian Cancer Society, What is Melanoma?

TYPES OF MELANOMA

There are three different types of melanoma:

Cutaneous Melanoma

There are four different types of cutaneous melanoma, which are determined by microscopic examination of a biopsy sample.

  • Superficial Spreading Melanoma counts for approximately 70% of melanomas of the skin. Superficial spreading melanoma usually develops from an atypical mole and can be found anywhere on the body.
  • Nodular melanoma makes up about 10-15% of melanomas. Nodular melanoma starts growing down into the skin and spreading quickly.
  • Lentigo maligna melanoma makes up about 10-15% of melanomas. Lentigo maligna melanoma is most often seen on skin that has been exposed to the sun. These spots are often large.
  • Acral lentiginous melanoma occurs as often in African Americans as in Caucasians. Acral lentiginous melanoma grows and spreads rapidly.
Mucosal Melanoma

Mucosal melanoma develops in the lining of the respiratory, gastrointestinal, and genitourinary tracts. It is a rare form of melanoma, making up only about 1% of melanoma cases and is often diagnosed at an advanced stage in the elderly. Approximately 50% of mucosal melanomas begin in the head and neck region, 25% begin in the ano-rectal region, and 20% begin in the female genital tract. The remaining 5% occur in the esophagus, gallbladder, bowel, conjunctiva, and urethra.

 

More information about mucosal melanoma can be found on the Melanoma Research Foundation website.

Ocular Melanoma

Ocular melanoma is rare, affecting approximately five in a million people. While it represents only 5% of melanomas, ocular melanoma is rapid and aggressive, accounting for 9% of melanoma deaths. There are no established risk factors for ocular melanoma, but it often occurs in blue-eyed, fair-skinned people over sixty years old. Treatment can be successful if the tumours in the eye are caught early. Around 50% of tumours will metastasize, usually in two to five years. Metastasis is to the liver in approximately 90% of cases, but can also occur in the lungs, bones, brain or abdomen.

 

More information about ocular melanoma can be found at Eye cancer Forum UKOcular Melanoma FoundationAlberta Health Service: Uveal Melanoma GuidelineCanadian Cancer SocietyBC Cancer Agency

PRECANCEROUS CONDITIONS: ACTINIC KERATOSIS AND BOWEN’S DISEASE

Precancerous conditions of the skin have the potential to develop into non-melanoma skin cancer. The most common precancerous conditions of the skin are actinic keratosis and Bowen’s disease.

Actinic Keratosis

Actinic keratosis is also called solar keratosis, and is often found on sun-exposed areas of the skin in people middle-aged or older.  A person with one actinic keratosis will often develop more. The number of actinic keratoses often increases with age. The presence of an actinic keratosis indicates that a person’s skin has suffered sun damage.

Actinic keratoses are considered slow growing. They often go away on their own, but may return. Approximately 1% of actinic keratoses develop into squamous cell carcinoma (SCC) if left untreated. Treatment is required because it is difficult to tell which keratoses will develop into cancer.

Watch our informative video about actinic keratosis here.

 

Risk Factors:

The following risk factors may increase a person’s chance of developing actinic keratosis:

  • Overexposure to ultraviolet B (UVB) radiation from the sun
  • Increased age
  • Fair skin
  • Weakened immune system
  • Previous PUVA (psoralen + UVA) therapy

 

Signs and Symptoms:

Actinic keratosis is most often seen on skin that is frequently exposed to the sun, such as the face, the backs of hands or a balding scalp. The signs and symptoms of actinic keratosis may include:

  • Small, rough patches that may be pink-red or flesh coloured
  • An initially flat surface that becomes slightly raised and wart-like

 

Diagnosis:

Actinic keratosis is diagnosed during an examination of the growth. If it does not go away with treatment or shows signs of developing into SCC, a skin biopsy will be done.

 

Treatment:

Treatment options for actinic keratosis depend on the number and location of keratoses. The treatment may include one or a combination of the following:

  • Topical chemotherapy
    • 5-fluorouracil (5-FU, Efudex)
    • Ingenol mebutate (Picato)
  • Topical biological therapy
    • Imiquimod (Aldara or Zyclara)
  • Cryosurgery
    • Often used on single spots
    • May also be used for many small, raised spots
  • Surgery
    • Simple surgical excision
    • Curettage and electrodesiccation
      • May be used on many large spots
  • Chemical peeling
  • Laser surgery
  • Photodynamic therapy

 

Information obtained from the Canadian Cancer Society.

Bowen's Disease

Bowen’s disease is an early form of squamous cell carcinoma (SCC). It may be called squamous cell carcinoma in situ. Bowen’s disease involves cancer cells in the epidermis or outermost layer of the skin. Although it can’t spread to the lymph nodes, Bowen’s disease can spread into the deeper layers of the skin if left untreated. When it spreads, it becomes an invasive SCC that then has the potential to spread into the lymph system.

 

Risk Factors:

The following risk factors may increase a person’s chance of developing Bowen’s disease:

  • Overexposure to ultraviolet B (UVB) radiation from the sun
  • Increased age
  • Previous radiation therapy
  • Weakened immune system
    • Infection with human papillomavirus (HPV) is associated with Bowen’s disease of the anal and genital skin
  • Arsenic exposure

 

Signs and Symptoms:

Bowen’s disease is most often seen on the legs, backs of hands, fingers or face. The signs and symptoms of Bowen’s disease may include:

  • A reddish scaly patch, which is sometimes crusted – may be a single patch or multiple areas
  • A windblown appearance of the skin
  • Larger, redder and scalier patches than actinic keratoses

 

Diagnosis:

If the signs and symptoms of Bowen’s disease are present, or if the doctor suspects Bowen’s disease, a biopsy will be done to make a diagnosis. The type of biopsy may be:

  • Shave biopsy
  • Punch biopsy

 

Treatment:

Treatment options for Bowen’s disease depend on the number and location of spots. The treatment may be one or a combination of the following:

  • Surgery
    • Simple surgical excision
    • Curettage and electrodesiccation
  • Topical chemotherapy
    • 5-fluorouracil (5-FU, Efudex)
  • Topical biological therapy
    • Imiquimod (Aldara or Zyclara)
  • Cryosurgery
  • Photodynamic therapy

 

Information obtained from the Canadian Cancer Society.

CONTRIBUTING FACTORS TO MELANOMA AND NON-MELANOMA SKIN CANCERS

The following may contribute to the development of melanoma and non-melanoma skin cancers. If you have any concerns about your skin and possible skin cancer, contact your physician immediately. More information about the diagnosis process can be found here.

 

  • Unprotected and/or excessive exposure to ultraviolet (UV) radiation
  • A fair complexion
  • The tendency to freckle
  • Occupational exposures to coal tar, pitch, creosote, arsenic compounds, or radium
  • Some medications, such as immunosuppressants
  • Family history of skin cancers
  • Multiple or atypical moles
  • Severe sunburns, especially as a child

monthly self-exams are key to early detection

Making awareness and education available is crucial. Since 2006, the Foundation has worked to raise awareness of melanoma and non-melanoma skin cancers focusing on education, prevention and the need for improved patient care.

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