Dermatoscope and patient

Have you ever wondered how your dermatologist diagnoses skin cancer? Why are they concerned about one spot on your skin, but not another? Today I will share some of the clues that we use when looking for skin cancers.

First, skin cancers are common. They affect millions of people every year. There are many types of skin cancers and some we see more often than others. The most common types of skin cancer are basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Another less common but potentially dangerous skin cancer is melanoma. Skin cancers are very treatable when they are caught early.

When diagnosing a skin cancer, I use the following:

Your history

The story of a spot can tell us a lot. Growing, bleeding, changing, or non-healing spots are all clues that may be worrisome. I also want to know how long the spot has been there, and if it has ever been treated before.

Your exam

When I look at your skin, I look for specific features. If there is a spot that bothers you, we will examine that area more carefully. When looking for common skin cancers like basal cell carcinomas or squamous cell carcinomas, I look for pink spots that might be more scaly or shiny than your normal skin or for sores that are not healing normally. When looking for melanoma, I look for brown spots that are different than others on your skin, particularly ones with irregular borders, different or numerous colors, and asymmetry. Dermatologists often will use a tool called a dermatoscope. A dermatoscope is a type of magnifier with a special light source that helps us to look at details of a pigmented spot. A dermatologist has been trained to identify certain findings that are either worrisome or reassuring using their dermatoscope. The dermatoscope improves diagnosis accuracy, helping to differentiate lesions of the skin from melanoma, thereby reducing unneeded biopsies.

Your prior treatments

If a spot has been treated previously (maybe it was frozen using cryotherapy) and came back, this may make us more suspicious that a spot could be a skin cancer.

What then?

If we are suspicious for a skin cancer, we will often recommend a biopsy. A biopsy involves numbing the skin, and taking a small sample. That small piece of skin is then examined under the microscope, and can tell us whether or not the spot is cancerous. If skin cancer is identified, we will recommend treatment. As I mentioned earlier, skin cancers that are caught early are very treatable. Finding and treating early skin cancers is an important part of my job as a dermatologist.

Contact Us for Care

If you have concerns about spots on your skin or any other skin-related concerns, contact The Polyclinic Dermatology Department at 206-860-5571 for expert diagnosis and treatment.


September 10, 2018 | by