How does your doctor find skin cancer?

We tell you what your doctor looks for and why.

December 8, 2020


A dermatologist is a doctor who specializes in the skin and skin problems, including skin cancer. This article goes over some of the clues that help dermatologists find skin cancer.

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.

What your doctor will ask about 

Your dermatologist will focus on three things:

  • Your history
  • Your exam
  • Prior care you have gotten 

The story of a spot can tell us a lot. Growing, bleeding, changing or nonhealing spots are all clues that may be worrisome. We also want to know how long the spot has been there, and if you have ever gotten care for it before.

When we check your skin, we look for specific features. If there is a spot that bothers you, we will look at that area more carefully. 

When looking for common skin cancers like basal cell carcinomas or squamous cell carcinomas, we 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, we look for: 

  • Asymmetry (spots that aren’t even)
  • Spots of different colors or many different colors in one spot
  • Brown spots that are different than others on your skin, particularly ones with irregular (not normal) borders

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 see certain findings using their dermatoscope. The dermatoscope improves how accurately we can find cancer. It also helps us tell the difference between normal lesions of the skin from melanoma. 

This exam helps lower your chances of having a biopsy you don't need. A biopsy is when a sample of tissue is taken from the body and tested. 

If you have had a spot cared for or removed before and it came back, this may make us more suspicious. It a spot comes back after it's been removed, it could be skin cancer. 

What to do about skin cancer

If we suspect skin cancer, we'll often suggest that you have a biopsy. This involves removing a small piece of skin and examining it under a microscope to see if it's cancerous.  

Contact us

If you have concerns about spots on your skin or any other skin-related concerns, contact The Polyclinic dermatology department at 1-206-860-5571 for expert diagnosis and treatment.

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The information provided is for general informational purposes only and is not intended to be medical advice or a substitute for professional health care. You should consult an appropriate health care professional for your specific needs.

A dermatologist is a doctor who specializes in the skin and skin problems, including skin cancer. This article offers insights into what makes a dermatologist more concerned about some spots on your skin and not others.