April 16, 2007

Paget's Disease, Squamous Cell Carcinoma


Paget's Disease
Paget's disease is a rare type of skin cancer that originates in glands in or under the skin.

The term Paget's disease also refers to an unrelated metabolic bone disease (see Paget's Disease of Bone); these distinct diseases should not be confused with each other.

Paget's disease occurs mainly on the nipple and is the result of a cancer of the breast milk ducts that has spread to the skin of the nipple. Men and women are both affected. The underlying cancer may or may not be felt by the person or the doctor. Sometimes, Paget's disease develops in the genital area or around the anus as the result of a cancer originating in underlying sweat glands or even in nearby structures such as the genitals, intestines, or urinary tract.

The skin in Paget's disease appears red, oozing, and crusting. It looks like an inflamed, reddened patch of skin (dermatitis). Itching and pain are common. Because Paget's disease looks very much like common dermatitis, a biopsy is necessary to make the diagnosis.

Paget's disease of the nipple is managed like other types of breast cancer. Paget's disease outside the breast area is treated by surgically

Squamous Cell Carcinoma
Squamous cell carcinoma is cancer that originates in the squamous cells (keratinocytes).

Squamous cells (keratinocytes) are the main structural cells of the epidermis. Squamous cell carcinoma usually develops on sun-exposed areas but may grow anywhere on the skin or in the mouth, where sun exposure is minimal. It may develop on normal skin but is more likely to develop in precancerous skin growths caused by previous sun exposure (actinic keratosis (see Actinic Keratoses: Precancerous Growths). Squamous cell carcinoma is characterized by its thick, scaly, irregular appearance. Fair-skinned people are much more susceptible to squamous cell carcinoma than darker-skinned people. This type of cancer is also more likely to develop in chronic sores—such as chronic skin ulcers—or in skin that has been scarred, particularly by burns.

Squamous cell carcinoma begins as a red area with a scaly, crusted surface that does not heal. As it grows, the tumor may become somewhat raised and firm, sometimes with a wartlike surface . Eventually, the cancer becomes an open sore and grows into the underlying tissue.

Most squamous cell carcinomas affect only the area around them, penetrating into nearby tissues. But some spread (metastasize) to distant parts of the body and can be fatal. Those that occur near the ears and lower lip are more likely to spread. Squamous cell carcinoma in the mouth often spreads.

Bowen's disease is an early form of squamous cell carcinoma that is confined to the epidermis and has not yet invaded the deeper layers of the skin. The affected skin is red-brown and scaly or crusted and flat, sometimes looking like a patch of psoriasis or dermatitis or a fungal infection (ringworm).

Diagnosis, Treatment, and Prevention

When doctors suspect squamous cell carcinoma, they perform a biopsy to differentiate this skin cancer from similar-looking diseases.

Doctors treat squamous cell carcinoma and Bowen's disease by scraping and burning the tumor with an electric needle (curettage and electrodesiccation) or by cutting the tumor out. A technique called Mohs' microscopically controlled surgery may be used. Sometimes radiation treatments are used. These treatments are usually effective, and most people survive.

Squamous cell carcinoma that has spread to other parts of the body can be fatal. It is treated with radiation or chemotherapy, but treatment may not be effective.

Because squamous cell carcinoma is often caused by sun exposure, people can help prevent this cancer by staying out of the sun and using protective clothing and sunscreen

Adapted from: Merck & Co. Inc.