What Are Moles and Melanoma?

Moles are clusters of pigmented cells that are often dark brown or black. Most moles are harmless and vary in shape and size, and some may even change shape and size without becoming cancerous. Moles that become painful, itch, bleed, or suddenly become asymmetrical, or change size, shape or color should be looked at by a dermatologist. Moles are more likely to become cancerous if they are large or atypical or if the patient has a lot of moles.

Northwestern Medicine provides diagnosis and treatment for moles and melanoma by conducting skin examinations, taking samples of suspicious-looking moles (biopsy) and removing moles with a scalpel (excision) or cutting around and underneath the mole (shaving) to leave healthy tissue. Our dermatologists may also recommend a yearly skin exam for people who have numerous moles or an increased risk of melanoma and skin cancer.

Use the ABCDE skin guide to determine if your moles need further examination.

  • A: Asymmetrical shape.
  • B: Border. Moles with borders that are not smooth are more likely to be cancerous.
  • C: Color. Look for moles with uneven color or changes in color.
  • D: Diameter. Most cancerous moles are larger than ¼ inch (the size of a pencil eraser), although not all large moles are cancerous.
  • E: Evolving. Look for moles that change in size or color, or become itchy and painful.

View Video: Skin Biopsy: Skin is the largest organ of the body and consists of three layers: the epidermis, dermis and hypodermis. This 3D medical animation depicts the anatomy and physiology of skin and demonstrates the different surgical techniques commonly used.

View Video: Skin Graft Procedure: Medical animation of a skin graft.

Meet The Teams

Northwestern Medicine dermatologists pride themselves on working with patients to find the best individualized treatment for their skin conditions, including eczema and skin allergies.