Malignant melanoma in situ affects only the top layer of skin. Fosko said it's nearly 99 percent curable if caught early, and is cut out of the skin during an outpatient procedure. It usually does not recur.
SKIN CANCER TYPES IN SLU STUDY
In 2004, the department of dermatology at St. Louis University saw 890 patients with non-midline skin cancer, where the cancer was clearly on one side of the body.
The patients' average age was 68; 557 of them (62.5 percent) were men.
Dr. Scott Fosko, chairman of the department of dermatology, breaks down their skin cancer diagnoses.
608 (68.3 percent) had basal cell carcinoma - It is nonfatal but can be disfiguring if not treated promptly. It appears as an open sore, reddish patch, shiny bump, pink growth or scar-like area.
178 (20 percent) had squamous cell carcinoma - It is curable but can become disfiguring if it penetrates underlying tissues. A small percentage metastasize to distant tissues and organs, and can be fatal. It can also recur after removal. It looks like a thick, scaly patch that can bleed if bumped.
42 (4.7 percent) had malignant melanoma in situ - It is confined to the top layer of skin and is nearly 100 percent curable. It appears as an irregularly shaped mole that's brown, asymmetrical and grows.
38 (4.2 percent) had squamous cell carcinoma in situ - It is on the top layer of skin. It's highly curable because it hasn't penetrated skin layers or spread to other tissues and organs.
23 (2.5 percent) had invasive malignant melanoma - It can quickly spread to lymph nodes and organs. It causes 75 percent of all skin cancer deaths. People who start using tanning beds before age 30 are 75 percent more likely to develop melanoma.
Visit skincancer.org for more information.