Understanding the Basic Anatomy of Skin

The skin is the largest organ of the human body and is responsible for protecting the body from external harm and regulating the internal temperature. The skin has a complex structure and a variety of functions. It is composed of three layers, the epidermis, dermis, and subcutaneous tissue. The epidermis is the outermost layer and acts as a barrier against the environment, while the dermis provides structural support and contains blood vessels, nerves, and hair follicles. The subcutaneous tissue is the deepest layer and contains fat and connective tissue.

What is Skin Cancer?

Skin cancer is a medical condition that occurs when abnormal cells grow in the skin tissues. Usually, old skin cells die, and new ones replace them. However, when this process is disrupted due to factors such as exposure to UV light from the sun, the cells may grow more rapidly. Some cells can be benign and not cause harm or spread, while others can be cancerous. These mutations lead the skin cells to multiply rapidly and form malignant tumours.

Failure to identify and treat skin cancer in its early stages can result in it spreading to nearby tissues or other parts of the body. Fortunately, skin cancer can be cured if detected early. Therefore, you must consult a healthcare provider if you notice any signs of skin cancer.

What are the types of skin cancers?

Skin cancer can be classified into three main types, including

  • Basal cell carcinoma arises from the basal cells found in the lower portion of the epidermis
  • Squamous cell carcinoma occurs in the squamous cells of the outermost layer of the skin.
  • Melanoma develops from melanocytes, responsible for producing melanin, the brown pigment that gives skin its colour and protects against harmful UV rays from the sun. Melanoma is the most severe type of skin cancer due to its potential to spread to other body parts.


Other types of skin cancer include Kaposi sarcoma, Merkel cell carcinoma, Sebaceous gland carcinoma and Dermatofibrosarcoma protuberances.

What are the signs and symptoms of Skin Cancer?

Skin cancer is often indicated by an alteration in the skin, usually in the form of new growth or changes in an existing mole or growth. Skin cancer symptoms can include various characteristics, such as

  • A newly formed mole, or a mole that has changed in size, shape, colour, or that bleeds
  • A waxy or pearly bump on the neck, face, or ears
  • A flat, pink, or brown-coloured bump or patch
  • An area on the skin resembling a scar
  • Sores that look crusty, bleed often, and with a central depression 
  • A wound or sore that does not heal, or if it heals, it comes back again
  • A rough, scaly lesion that may itch, bleed, or become crusty

Less common types of skin cancer may have different signs and symptoms. These include:

  • Kaposi sarcoma: This is a rare form of skin cancer that develops in the skin’s blood vessels and causes red or purple patches on the skin or mucous membranes. It is more common in individuals with weakened immune systems, such as people with AIDs or those taking immunosuppressive medications following organ transplant.
  • Merkel cell carcinoma: This is characterized by the formation of firm, shiny nodules that emerge on or below the skin and within hair follicles. It is commonly observed on the head, neck, and trunk.
  • Sebaceous gland carcinoma: This is an uncommon and aggressive cancer that initiates in the skin’s oil glands. It usually appears as hard, painless nodules. Sebaceous gland carcinoma can develop anywhere on the body. However, they are most commonly found on the eyelid, often leading to misdiagnosis as other eyelid conditions.

What are the most common sites for Skin Cancer?

Skin cancer typically develops on skin exposed to the sun, such as the face, scalp, lips, ears, neck, arms, hands, and chest. However, it can also appear in areas that receive minimal sun exposure, such as the genital area, beneath the fingernails or toenails, or on the palms of the hands. When melanoma occurs in people with darker skin, it is more likely to develop in areas that are typically not exposed to the sun, such as the soles of the feet or palms of the hands.

What does Skin Cancer look like?

kin cancer varies depending on the type of skin cancer. To identify potential warning signs, it is helpful to remember the ABCDE rule:

  • Asymmetry: irregular shape.
  • Border: blurry or irregularly shaped edges.
  • Colour: a mole with more than one colour.
  • Diameter: larger than a pencil eraser (6 millimetres).
  • Evolution: enlarging, changing in shape, colour, or size, which is the most significant sign.

What are the risk factors for Skin Cancer?

Although anyone can develop skin cancer, you are at increased risk if you are:

  • Spending significant time outside in the sun for work or recreational activities.
  • Having a history of sunburns or easily getting sunburned or blisters.
  • Living in a location with high levels of sun exposure or at high altitudes.
  • Having fair or freckled skin, light-coloured eyes, and blond or red hair.
  • Having many moles or unusual moles.
  • Having actinic keratosis which is precancerous skin growths that appear as scaly, dark pink-to-brown patches.
  • Having a family history of skin cancer.
  • Undergoing an organ transplant.
  • Taking medications that weaken the immune system.
  • Individual with fair skin complexion
  • Receiving UV light therapy for skin conditions such as eczema or psoriasis.
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How to perform a skin self-examination?

Performing a regular skin self-examination is an important practice for early detection of skin cancer. Here is a step-by-step guide on how to perform a skin self-exam:

  • Find a well-lit room with a full-length mirror: Make sure you have adequate lighting and a large mirror that allows you to see your entire body.
  • Look at your underarms, forearms, and palms:  Look carefully at the front and back of your hands, including your wrists. Examine your palms, fingers, and the spaces between your fingers. Do not forget to check your forearms and upper arms as well.
  • Look at your legs, between toes, and soles of the feet: Sit down and carefully examine the soles of your feet, including the spaces between your toes. Use a handheld mirror or ask for assistance to check the tops of your feet.
  • Use a hand mirror to check your neck and scalp: Using a comb or a hairdryer, part your hair to check your scalp thoroughly. If necessary, you can ask someone for assistance in examining areas that are difficult to see.
  • Focus on your lower body: While facing the mirror, examine your lower body, including your buttocks, genitals, and the front and back of your thighs. Do not forget to check your knees, calves, ankles, and the soles of your feet.

What tests will be done to diagnose Skin Cancer?

Initially, a dermatologist may inquire if you have observed any alterations in pre-existing moles, freckles, or other skin spots, or if you have detected any new skin growths. They will then inspect all of your skin, including your scalp, ears, palms, soles, interdigital areas, and perianal region. A skin cancer diagnosis always requires a skin biopsy, which a dermatologist does. A skin biopsy is crucial because it is the only way to confirm the presence of skin cancer. The removed tissue will be examined under a microscope for cancer cells. If cancer cells are present, the biopsy report will specify what type of skin cancer cells were found.

What are the stages of Skin Cancer?

The stages of skin cancer are as follows:

  • Stage 0: Cancer is limited to the top layer of the skin.
  • Stage I (1): Cancer has invaded the top and middle layers of the skin.
  • Stage II (2): Cancer has invaded the top and middle layers of the skin and may have spread to the nerves or deeper layers of the skin.
  • Stage III (3): Cancer has spread beyond the skin to the lymph nodes.
  • Stage IV (4): Cancer has spread to other organs, such as the liver, lungs, or brain.

What are the treatment options available for Skin Cancer patients?

Skin cancer treatment depends on the type, size, and location of the cancer and the patient’s overall health. Treatment options include:

  • Surgery: This involves the removal of the cancerous growth and some surrounding healthy tissue to ensure that all cancer cells are eliminated.
  • Radiation therapy: Uses high-energy radiation to destroy cancer cells and is often used for small, early-stage skin cancers.
  • Topical medications: Creams or ointments containing chemotherapy drugs or immunotherapy drugs can be applied to the skin to destroy cancer cells.
  • Mohs surgery: Mohs surgery is a specialized procedure used to treat larger, recurring, or challenging-to-treat skin cancers, including basal cell carcinoma and squamous cell carcinomas. In Mohs surgery, the surgeon removes the skin growth layer by layer, carefully examining each layer under a microscope. This process continues until no abnormal cells are detected. By doing so, cancerous cells can be effectively removed while minimizing the removal of surrounding healthy skin.
  • Cryotherapy: Involves freezing the cancerous growth with liquid nitrogen, causing it to die and fall off.
  • Photodynamic therapy: This involves the use of a photosensitizing agent and a special light source to destroy cancer cells.
  • Chemotherapy: This involves using drugs to kill cancer cells and is typically used for advanced cases of skin cancer.

How can I lower my risk of developing Skin Cancer?

Protecting yourself from skin cancer can be done by following these steps:

  • Apply a broad-spectrum sunscreen with SPF 30 or higher before going outside. Use it every day, including on cloudy days and during winter.
  • Wear wide-brimmed hats, long-sleeved shirts, pants, and sunglasses that block UV rays.
  • Use a lip balm with sunscreen to protect your lips.
  • Avoid being in the sun between 10 a.m. and 4 p.m.
  • Check with your healthcare provider if your medication makes your skin sensitive to sunlight.
  • It is essential to regularly examine your entire body for any changes in size, shape, or colour of skin growths, as well as the emergence of new skin spots

When should I see my healthcare provider?

It is advisable to schedule an appointment with a healthcare provider or dermatologist promptly if you experience any of the following:

  • Noticeable changes in your skin or alterations in the size, shape, or colour of existing moles or other skin lesions.
  • The sudden appearance of new growth on your skin.
  • Persistent sores that do not heal.
  • Spots on your skin that look distinct from others.
  • Any spots that undergo changes, itchiness, or bleeding.


By seeking medical attention, your healthcare provider or dermatologist will examine your skin, conduct a biopsy, provide a diagnosis, and discuss appropriate treatment options.

Additionally, it is recommended to have an annual comprehensive skin review performed by a dermatologist to monitor any potential changes or concerns

Conclusively, skin cancer is a condition that can affect anyone, even if a seemingly harmless blemish could be a sign of it. Everyone must conduct routine self-examinations of their skin, but it is particularly vital for those with a higher risk of skin cancer.

The key to curing almost all skin cancers is catching and treating them before they spread. The earlier the diagnosis and removal, the higher the chances of a full recovery. Regular check-ups with a dermatologist are important to monitor for any recurrence.

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