Melanoma is a form of skin cancer. It arises from specialized skin cells called melanocytes, which produce the color (pigment) in our skin.
Melanomas are pigmented lesions that resemble normal skin moles. **However, melanomas usually have characteristics that distinguish them from moles.
** Being aware of the differences between moles and melanomas enables you to monitor your skin for the possible development of melanoma. Five distinguishing characteristics to look for are represented by the mnemonic ABCDE where “A” is for asymmetry, “B” is for border irregularity, “C” is for color variegation, “D” is for diameter and “E” is for evolving.
Normal moles—called nevi—are typically symmetrical, which means that if you were to draw a line down the middle of it, the two halves would look like mirror images of each other. Melanomas are most often asymmetrical. If you drew an imaginary line down the middle of a melanoma, the two sides would not look alike.
- Normal moles—called nevi—are typically symmetrical, which means that if you were to draw a line down the middle of it, the two halves would look like mirror images of each other.
What Kinds of Growths Form on Aging Skin?
The border or edge of a mole is generally smooth and distinct. It is clear where the mole ends and the regular skin begins. Melanomas typically have irregular borders that may have a blurry appearance. Melanomas may have a white ring or halo around them, which is an area of skin without any pigment surrounding the lesion. Melanomas may also have satellites, tiny areas of pigment that are beyond what appears to be the border of the lesion.
- The border or edge of a mole is generally smooth and distinct.
- Melanomas may also have satellites, tiny areas of pigment that are beyond what appears to be the border of the lesion.
A normal mole is usually a single color. In contrast, melanomas are typically more than one color.
Shades of tan, brown and black are common in melanomas. Small areas of white, red and blue may also be present. Sudden darkening of a preexisting mole may be a sign that it has transformed into a melanoma.
- A normal mole is usually a single color.
- In contrast, melanomas are typically more than one color.
Age Spots and Moles
Most melanomas measure more than 6 millimeters across--about as big around as the diameter of a pencil. Although some melanomas are smaller than 6 millimeters and some moles are larger than 6 millimeters, using this cutoff can help determine if a lesion is suspicious.
Evolution in this context refers to whether a lesion is changing.
Moles generally do not change, or they change slowly over many years.
In contrast, melanomas can change rather quickly. They may change in size, shape, color or other ways such as becoming ulcerated or beginning to itch.
Evolution also refers to a lesion that is unlike the others.
If a spot on your skin looks like all your other moles, then it probably is just another mole. However, if the spot is different from your other moles in one or more ways, that could be a red flag for melanoma.
- Evolution in this context refers to whether a lesion is changing.
Melanomas can have surface characteristics that moles usually do not have. These include scaliness, crusting, oozing, ulceration and bleeding.
Melanomas can cause symptoms that moles usually do not. A pigmented skin lesion that is painful, tender or itches is suggestive of a melanoma.
Melanoma is a potentially deadly cancer, which typically shows some or all of these ABCDE changes. Other times the changes can be subtle and difficult to appreciate. If you notice a suspicious spot on your skin, see your doctor to have it checked. Early detection is the key to survival with melanoma 2.
- Melanomas can cause symptoms that moles usually do not.
- A pigmented skin lesion that is painful, tender or itches is suggestive of a melanoma.
What Kinds of Growths Form on Aging Skin?
Age Spots and Moles
What if an Age Spot Is Changing & Itchy?
Examples of Harmless Skin Moles
Facts About Red Moles
Why Is a Mole Raising Up on Skin?
Melanoma Vs. Age Spots
Skin Moles in Children
Early Signs of Skin Cancer and Penile Cancer
Actinic Keratosis Vs. Seborrheic Keratosis
- “Clinical Oncology, Third Edition”; Martin D. Abeloff, M.D., James O. Armitage, M.D., John E. Niederhuber, M.D., Michael B. Kastan, M.D., Ph.D., W. Gilles McKenna, M.D., Ph.D., Editors; 2004
- “American Academy of Dermatology”: Melanoma: What it looks like
- “Clinical Dermatology: A Color Guide to Diagnosis and Therapy”; Thomas P. Habif, M.D.; 1996
- Matthews NH, Li WQ, Qureshi AA, et al. Epidemiology of Melanoma. In: Ward WH, Farma JM, editors. Cutaneous Melanoma: Etiology and Therapy. Brisbane (AU): Codon Publications; 2017 Dec 21.
- Potrony M, Badenas C, Aguilera P, et al. Update in genetic susceptibility in melanoma. Ann Transl Med. 2015;3(15):210. doi:10.3978/j.issn.2305-5839.2015.08.11
- Bhatt M, Nabatian A, Kriegel D, Khorasani H. Does an increased number of moles correlate to a higher risk of melanoma?. Melanoma Manag. 2016;3(2):85-87. doi:10.2217/mmt-2016-0001
- Heistein JB, Acharya U. Cancer, Malignant Melanoma. [Updated 2019 Mar 12]. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2019 Jan-.
- Addepally NS, Klair JS, Lai K, Aduli F, Girotra M. Primary Bile Duct Melanoma Causing Obstructive Jaundice. ACG Case Rep J. 2016;3(4):e128. doi:10.14309/crj.2016.101
- Daniel jensen J, Elewski BE. The ABCDEF Rule: Combining the "ABCDE Rule" and the "Ugly Duckling Sign" in an Effort to Improve Patient Self-Screening Examinations. J Clin Aesthet Dermatol. 2015;8(2):15.
- Wehner MR. Sunscreen and melanoma prevention: evidence and expectations. Br J Dermatol. 2018;178(1):15-16. doi:10.1111/bjd.16111
- Silva ESD, Tavares R, Paulitsch FDS, Zhang L. Use of sunscreen and risk of melanoma and non-melanoma skin cancer: a systematic review and meta-analysis. Eur J Dermatol. 2018;28(2):186-201. doi:10.1684/ejd.2018.3251
- Ombra MN, Paliogiannis P, Doneddu V, et al. Vitamin D status and risk for malignant cutaneous melanoma: recent advances. Eur J Cancer Prev. 2017;26(6):532-541. doi:10.1097/CEJ.0000000000000334
- National Cancer Institute. Melanoma Treatment – for Health Professionals (PDQ). Updated 02/02/16.
Dr. Tina M. St. John owns and operates a health communications and consulting firm. She is also an accomplished medical writer and editor, and was formerly a senior medical officer with the U.S. Centers for Disease Control and Prevention. St. John holds an M.D. from Emory University School of Medicine.