Your skin is your body’s largest organ and it serves several important functions. Your skin protects your body from heat, injury and infection; stores necessary water and fat; helps maintain body temperature; and makes vitamin D, an essential nutrient. The skin consists of two main layers:
Epidermis – This outer, top skin layer is where most skin cancers begin. The epidermis contains four types of cells:
- Squamous cells are the thin flat cells of the outer skin layer. Squamous cell carcinoma is skin cancer that begins in the squamous cells.
- Basal cells are round skin cells that lie under the squamous cells, deeper in the skin. Basal cell carcinoma is skin cancer that begins in the basal cells.
- Merkel cells are among the basal cells in the deepest epidermis layer. These cells are connected to the nerves endings. Merkel cell carcinoma is rare cancer that begins in the Merkel cells.
Read more about Merkel Cell Carcinoma
- Melanocytes are scattered among the basal cells and make melanin, the pigment that colors your skin. Melanoma, is a skin cancer type that begins in the melanocytes.
Dermis – This deeper, skin layer contains blood vessels, lymph vessels, nerves, sweat and oil glands and hair follicles, which are all held in place by a protein called collagen.
Under the dermis lies the subcutis or hypodermis. This layer is not part of the skin, but connects the skin to muscles and bones. It consists of collagen and fat cells that conserve body heat and act as a shock absorber to protect organs from injury.
Risk Factors & Symptoms
Risk factors for non-melanoma skin cancers include:
- Sunlight (ultraviolet radiation or UV) exposure
- Severe, blistering sunburns
- Personal history of a previous skin cancer
- Receiving an organ transplant
- Family history of skin cancer
- Fair complexion (including blonde or red hair, blue eyes, skin that freckles or burns easily)
- Disease that weakens the immune system such lymphoma, leukemia or human immunodeficiency virus (HIV)
- Old scars, burns, ulcers or inflamed skin areas
- Actinic keratosis (AKs)
- Gorlin’s Syndrome – Also called basal cell nevus syndrome. May cause many basal cell carcinomas early in life.
- Xeroderma pigmentosum – A rare, inherited condition where the skin has an extreme reaction to sunlight and cannot heal well.
- Radiation therapy
- Exposure to chemicals like arsenic, coal or industrial tar
- Smoking or chewing tobacco
- Human papillomavirus (HPV) – Some HPV types infect the skin and increase risk for skin cancer. These are different HPV types from those that cause cervical or genital cancers
Indoor Tanning Dangers
Artificial sources of UV radiation, such as sun lamps, tanning beds and booths are more dangerous than sunlight because their UV radiation is stronger. The World Health Organization declared these tanning devices to be a group 1 carcinogen, putting them in the same group as tobacco, asbestos and uranium as a definite cause of cancer. People who use tanning beds have a much higher risk for getting skin cancer and they tend to get skin cancer earlier in life.
Symptoms of Non-Melanoma Skin Cancer:
- A change on the skin (a new lump or growth, change in an old lump or growth, or a sore that doesn’t heal)
- A red or brown patch that’s rough and scaly
- Patch or growth may become itchy or tender but usually skin cancer is not painful
Merkel Cell Carcinoma: Rare and Aggressive
Merkel cell carcinoma is a rare, aggressive neuroendocrine cancer that occurs in the skin. These cancers tend to grow quickly and metastasize (spread) even at an early stage, first to nearby lymph nodes and then to distant sites such as the lungs, brain, bones and other organs.
Merkel cell carcinomas tend to occur as a single painless lump that is:
- Firm, dome-shaped or raised
- Red or violet