Conditions: Skin Cancers
Sun or other ultraviolet light exposure is the #1 risk factor for skin cancers, but fair skin, family history of skin cancers, and a personal history of other skin cancers also increase one’s odds of developing a new skin cancer. Non-cancerous lesions of the skin are discussed elsewhere.
squamous cell carcinoma of the skin
Squamous cell skin cancer, also known as cutaneous squamous-cell carcinoma, is one of the common types of skin cancer. It usually presents as a hard lump with a scaly top but can also form an ulcer, slowly growing over months. It is usually painless. Squamous cell carcinoma has the potential grow into surrounding tissues, spread (metastasize) to nearby lymph nodes, or travel along nerves, though these events are not frequent when the cancer is identified and treated early. Spread to other organs (such as the lung) is very unlikely to happen before having spread to nearby lymph nodes first. The risk of spread to lymph nodes is primarily related to the size of the tumor itself.
basal cell carcinoma
Basal-cell carcinoma (BCC), also known as basal-cell cancer, is the most common type of skin cancer. It often appears as a painless raised area of skin, which may be shiny with small blood vessels running over it. It may also present as a raised area with ulceration. Basal-cell cancer grows slowly and can damage the tissue around it, but it is very unlikely to spread to distant areas or result in death. A less common variant, called basosquamous cell carcinoma has features of basal cell carcinoma and squamous cell carcinoma, but behaves like the more aggressive squamous cell carcinoma.
Risk factors include exposure to ultraviolet light, having lighter skin, radiation therapy, long-term exposure to arsenic and poor immune-system function. Exposure to UV light during childhood is particularly harmful. Tanning beds have become another common source of ultraviolet radiation. Diagnosis often depends on skin examination, confirmed by tissue biopsy.
In the United States, about 35% of white males and 25% of white females are affected by BCC at some point in their lives.
melanoma
Melanoma is a a cancer arising from pigment producing cells called melanocytes, and usually occurs on the skin, but may occur in the digstive tract, nose or sinuses, and eyes. Because of the type of cell involved, melanomas tend to be pigmented—brown or black. Overall, melanoma is the most dangerous type of skin cancer owing mainly to its notable ability to spread to lymph nodes or other organs.
Merkel cell carcinoma. Photo courtesy of dermnetnz.org
merkel cell carcinoma
Merkel cell carcinoma is a rare but aggressive skin cancer typically occurring in the skin of the head or neck. It is more common in caucasians and in males. They are usually in the form of a firm nodule, and may be colored red, blue, or natural skin color. Risk factors include age over 60 years old, significant sun exposure, a weakened immune system, and/or exposure to the Merkel cell polyomavirus. This type of cancer behaves similarly to melanoma, in that it has significant potential to spread to lymph nodes or other organs of the body. Diagnosis is made by biopsy.