Types of Moles (and When to Consider Getting One Checked)

The three types of skin moles are common nevus, atypical (dysplastic) nevus, and spitz nevus. They may be congenital (present at birth) or acquired. Within these types are noncancerous and potentially cancerous moles.

This article explains types of moles, including those that are benign (noncancerous) and those that may be potentially cancerous. It also covers mole look-alikes and when to have a mole removed and biopsied.

Every Type of Mole

Nearly every adult has at least a few moles. Most of these moles are common, harmless moles. However, some types increase your chances of developing melanoma, the most serious type of skin cancer. Nevus (plural nevi) is a medical term for skin mole.

Noncancerous

A harmless mole is a common, noncancerous, or benign mole. Most adults have between 10 and 40 of these types of moles, which usually appear in areas most exposed to the sun.

Common moles have the following characteristics:

• Smaller than the width of a pencil eraser
• Round or oval
• Surface is smooth
• Edges are distinct
• Even colors of pink, tan, or brown
  

Spitz nevi are moles that look like melanoma but are benign. These moles grow very quickly and are most often found in younger people—70% are found in people under age 20. These moles can sometimes bleed or itch. They usually have a uniform pink, red, tan, blue, or black color. They are most common on the face, neck, and legs.

Potentially Cancerous

A dysplastic nevus is a type of mole that can develop into cancer. These types of moles are also referred to as atypical moles.

Like common moles, these appear on areas most exposed to the sun but may also appear on other areas more commonly covered, like the chest and below the waist.

Characteristics of dysplastic nevi include:

• Bigger than a pencil eraser
• May be a mixture of multiple colors, from pink to dark brown
• Usually flat
• May be smooth, slightly scaly, or pebbly
• Irregular edges

People with dysplastic nevi also tend to have more common moles. An atypical mole is considered a risk factor for developing melanoma. Studies have found that around 20% of melanomas arise from dysplastic nevi. However, most dysplastic nevi do not become melanoma.

Congenital moles are those you are born with. A very large congenital mole (greater than 20 centimeters or 8 inches in diameter in adulthood) has an increased risk of melanoma.

Acquired moles appear after birth. If you have 50 or more common acquired moles, you have an increased risk of melanoma.

What Types of Moles Need to Be Checked?

Sometimes, it can be difficult to tell whether a mole is potentially cancerous. The acronym ABCDE can be used to watch for melanoma warning signs. The signs are:

• Asymmetry: If the mole were folded in half, the edges would not match.
• Border: Edges are irregular.
• Color: The color is not uniform.
• Diameter: The mole is larger than a pencil eraser.
• Evolving: It changes size, shape, or color.

Moles that have uneven shapes or whose borders are irregular are concerning. You should see a healthcare provider for an evaluation if you have a mole with any of the above characteristics.

Things That Look Like Moles But Aren't

Several skin growths are sometimes mistaken for moles. The following skin growths look like moles but are not.

Dermatofibroma

A dermatofibroma (also called fibrous histiocytoma) is a noncancerous skin growth that often appears on the legs, arms, and back. These growths are most common in middle age and are often associated with previous minor trauma, like an insect bite.

You can tell the difference between a mole and a dermatofibroma by pinching it. A dermatofibroma creates a dimple when squeezed, while a mole pulls away from the skin.

Hemangioma

A hemangioma is a noncancerous tumor made up of tiny blood vessels. They can occur in many places in the body, including the skin. These growths are common in infants and may be present at birth or appear within the first months of life.

They appear as red or blue lesions on the skin and are soft. Some people prefer to have these removed for cosmetic reasons.

Pilar Cysts

Pilar cysts are a subtype of sebaceous cysts. They are benign masses commonly found on the scalp, back, and face. They occur from the buildup of keratin (a protein in skin cells) in skin pores.

These growths occur in about 10% of the population. They feel like a firm nodule that moves around when you touch it.

Lipoma

Lipomas are noncancerous growths that occur under the skin. They can also grow around organs. These growths are made up of fat tissue. They are usually painless and found on the back, arms, buttocks, and thighs.

They can occur at any age but are most common in middle age. These growths feel soft and rubbery and can move around when you push them.

Seborrheic Keratosis

Seborrheic keratosis, commonly called skin barnacles, appear as wart-like growths anywhere on the skin. These growths are most common after 50. They appear waxy in texture and may be brown, white, or black.

Skin Tag

Skin tags are small, harmless growths that hang like a tag from your skin. They are more common as people age. While they are not medically concerning, they sometimes get caught on clothing or become irritated from rubbing between skin. For that reason, sometimes people have them removed.

Warts

A wart is a small bump on the skin caused by the human papillomavirus (HPV). Usually, warts are painless, but sometimes they can cause itching or pressure. Warts often go away on their own within a few weeks or months. They are contagious and very common.

Cherry Angiomas

Cherry angiomas are benign skin growths made up of clumped tother blood vessels. They are most common in adults over age 30. About half of adults have them, and up to 75% of people over 75 have them.

As their name implies, they are usually red, pink, or purple. They can be raised or flat and are generally quite small, perhaps the size of a pinhead.

Why Do Some People Have More Moles?

Heredity is usually to blame for people with many moles. If your parents have a lot of moles, you probably will too.

In addition, people who spend a lot of time in the sun may have more moles than people who don't. However, that is not entirely to blame since moles often appear in areas not exposed to the sun's rays. Gene variations are involved in benign moles.

Mole Removal and Biopsy

Most of the time, you don't need to have a mole removed. However, if a healthcare provider believes it looks suspicious or if a mole bothers you, you might decide to have it removed.

Not all moles require a biopsy (sample collected and analyzed in the lab) when removed. For example, if you have a mole removed for cosmetic reasons or because it's bothering you, you might not need a biopsy. However, sometimes, a dermatologist (a doctor specializing in skin conditions) will order a biopsy just to be safe.

Moles are most often removed by surgical excision or surgical shave. Both can be done in a healthcare provider's office with local anesthetic.

With an excision, a healthcare provider uses a scalpel to cut the mole out, then stitches the area closed, if necessary. With a shave, the healthcare provider uses a surgical blade to scrape the mole off the skin. The mole will be sent to a lab for evaluation if a biopsy is required.

Summary

Mole types include common, atypical (dysplastic), Whether you are born with moles or develop them later in life, it's good to know which moles may be more likely to be benign or cancerous.

Following the ABCDEs—asymmetry, borders, color, diameter, and evolution—when checking your skin can help you be aware of moles that may require an evaluation. Check your skin regularly to be aware of new moles and moles that change over time.