How to Spot an Atypical Mole

NORMAL MOLES are common small brown spots or growths on the skin that appear in the first few decades of life in almost everyone. They can be either flat or elevated and are generally round and regularly shaped. Many are caused by sun exposure.

MELANOMA, one of the deadliest forms of skin cancer, most often appears as an asymmetrical, irregularly bordered, multicolored or tan/brown spot or growth that continues to increase in size over time. It may begin as a flat spot and become more elevated. In rare instances, it may be amelanotic, meaning it does not have any of the skin pigment (melanin) that typically turns a mole or melanoma brown, black or other dark colors. In these cases, it may be pink, red, normal skin color or other colors, making it harder to recognize as a melanoma.

Sometimes it can be hard to tell the difference between an atypical mole and an early melanoma. (Some melanomas begin within an atypical mole.) The degree of atypical features in the mole can determine whether it is harmless, or at moderate or high risk of becoming a melanoma. Many physicians examine such moles with a dermoscope, a handheld magnifying device that allows visualization of internal skin structures and colors not seen by the naked eye. The doctor may also opt to remove the entire mole or a portion of it for examination in a lab.

Certain factors can be clear warning signs that an atypical mole is actually a melanoma or in danger of becoming a melanoma. These include itching, pain, elevation, bleeding, crusting, oozing, swelling, persisting open sores, bluish-black color and other features that may go right up to the edges of the mole. If you or a loved one has any of these warning signs, consult a dermatologist or another physician with experience in skin disorders.

Physicians can often identify an atypical mole by the same classic “ABCDE” characteristics used to identify a possible melanoma:

Asymmetry: Unlike common moles, atypical moles are often asymmetrical: A line drawn through the middle would not create matching halves.

Border: While common moles usually have regular, sharp, well-defined borders, the borders of atypical moles tend to be irregular and/or hazy — the mole gradually fades into the surrounding skin.

Color: Common moles are most often uniformly tan, brown or flesh-colored, but atypical moles have varied, irregular color with subtle, haphazard areas of tan, brown, dark brown, red, blue or black.

Diameter: Atypical moles are generally larger than 6 mm (¼ inch), the size of a pencil eraser, but may be smaller.

Evolution: Enlargement of or any other notable change in a previously stable mole, or the appearance of a new mole after age 40, should raise suspicion.

atypical mole with ABC warning signs
Atypical mole with asymmetry, border irregularity and multiple shades of brown.
atypical mole with ABCD warning signs
Atypical mole with asymmetry, border irregularity, color variations and diameter greater than ¼ inch
atypical mole on lower back
Atypical mole on lower back. Close-up of mole (on right) shows asymmetry, color variegation and border irregularity.

Other factors besides the ABCDEs may also indicate an atypical mole:

Surface: Central portion often is raised, whereas the peripheral portions are usually flat, sometimes with tiny “pebbly” elevations.

Varying Appearance:Atypical moles can be greatly varied, often looking different from one another.

atypical mole with melanoma
Melanoma arising in an atypical mole with asymmetry, scalloped border irregularity and color variegation, 1/3 inch.
atypical mole with varied appearance
Melanoma arising in an atypical mole with asymmetry, border irregularity and black, brown and tan color variegation, ½ inch.

Don’t wait for more serious warning signs of melanoma to appear, such as:

  • Itching
  • Pain
  • Elevation
  • Bleeding
  • Crusting
  • Swelling
  • Oozing
  • Ulceration
  • Bluish-black color
Precautions for Those with
Atypical Moles
Treatment for
Atypical Moles

Medical Reviewers:
Leonard H. Goldberg, MD
Mark Lebwohl, MD